How to use SIMBLIP

SIMBLIP is an engineering notebook where the things you draw can be simulated. Notes, sketches, circuits, equations, graphs, code and live experiments all live on the same canvas, in the same pages, inside the same notebook tree.

It is not a drawing app with a physics demo bolted on, and not a physics simulator with a notes tab. There is one document model: everything on a page is an object, and any object can be given physical meaning. That is why a pendulum can sit next to the paragraph explaining it, share a variable with the graph plotting it, and keep running while you edit both.

SIMBLIP is licensed to institutions rather than sold as individual accounts. Your school, college or university is provisioned as a tenant, and you sign in with the account it issues you. Which parts of the app you see depends on your role — see Classroom platform.

Every object on a page is dumb geometry — a circle, a rectangle, a polygon, a line, a pen stroke, a piece of text, a schematic symbol — plus a list of behaviors attached to it. The geometry decides what it looks like. The behaviors decide what it does.

• A circle with nothing attached is a drawing.
• The same circle with a Rigid Body attached has mass, falls, collides and spins.
• With a Static Body instead, it is an immovable wall.
• With a Motor, it drives its own rotation. With a Charge, it responds to electric fields.

Nothing in the palette is privileged. A Mass from the Components panel is literally a circle with a Rigid Body pre-attached — you could have drawn the circle and attached the behavior yourself, and the result would be identical. The palette saves clicks, it does not unlock anything.

Five minutes, no prior setup. From a signed-in notebook:

1. 1Create a page. In the notebook tree press + and pick Whiteboard — an infinite board is the simplest surface to experiment on.
2. 2Open Components in the left rail, stay on the Mechanics tab, and click Ground. Now click low down on the canvas to place it. The component stays armed, so you can place several.
3. 3Click Mass and drop one well above the ground. Press Esc to go back to the Select tool.
4. 4Press Play on the transport (or Q). The mass falls, lands, and settles. Press Reset (R) and it returns to exactly where you drew it — the simulation never edits your scene.
5. 5Select the mass and open Properties. Change Elasticity to 0.9 and press Play again. Now it bounces. You can change it while it is running.
6. 6Draw a circle with the Pen anywhere on the page, select it, and in Properties choose Add behavior → Rigid Body. Press Play. Your doodle falls too — that is the whole model in one gesture.

Edit

Playing

At rest

There is no public sign-up. Your institution issues your account, and signing in at /login drops you into /notebook — your personal workspace inside that institution. The landing page redirects you there automatically if you are already signed in.

Your notebooks are yours. Things other people give you — shared pages, assignments, library assets — always arrive as copies, so nothing you receive can change under you and nothing you edit can damage the original.

Your work is stored on the device first, so the notebook keeps working on a flaky network or none at all. Cloud sync is something you switch on per page rather than a blanket upload — see Data, storage and sync.

The desktop workspace has five fixed pieces:

Header

Global search, undo/redo, the open-page tab strip, per-page controls, sync status, notifications and your account menu.

Left rail

A column of icons — Notebook, Assistant, Components, Tools, Uploads, Library, Properties and (when the page has one) Contents. Clicking one opens its panel; clicking it again collapses the panel back to the rail.

Canvas

The page itself. Infinite and pannable on a board; a fixed stack of sheets on a document; a scrolling reader on a PDF.

Dock

The floating tool bar — Select, Pen, Shaper, Eraser, Text, Note, Formula, Graph, Grid Table, shapes and colour. It can be pinned to any edge or dragged loose.

Transport

Play, Pause, Step and Reset, plus the simulation clock. It is the only control that starts or stops physics.

On a phone this becomes a navigation app instead: Home → notebook → editor, with a bottom tab bar and properties as a sheet. See Touch, tablet and mobile.

Every page you open becomes a tab in the header strip, browser-style. Click a tab to focus it, × to close it. The strip scrolls horizontally when it fills up.

The split icon on a tab adds it as a second pane beside the current one — up to four panes at once, each resizable by dragging the seam between them. A PDF on the left and a board on the right is the common case: read the problem, build the answer.

• Pan — hold Space and drag, drag with two fingers, or scroll.
• Zoom — Ctrl/⌘ + scroll wheel, pinch on a touchscreen, or the zoom controls in the header.
• Fit the page — Ctrl+9. Back to 100% — Ctrl+0.
• Measure — hold Alt and drag between two points for a live distance readout.
• Mini-map — appears once a page has enough objects to get lost in. Object positions show as dots, your viewport as a rectangle; click to jump.

Scroll direction, grid style and grid size are all preferences — Settings → Editor. Pinch sensitivity, hold-before-drag and palm rejection are under Settings → Gestures.

Play / Pause

Starts or freezes the simulation. Q.

Step forward / back

While paused, advances or rewinds one frame — E and W. The way to catch the exact instant of a collision.

Reset

R. Throws away the running world and restores the scene exactly as drawn. Editing while paused or running is safe: Reset always returns to your edited scene, never to an earlier snapshot of it.

Clock

Elapsed simulated time, which is not the same as wall-clock time.

Ctrl/⌘+K opens one search box over everything: your pages, your notebooks, library assets, and the entire component palette. Picking a page opens it; picking a component drops it straight onto the page you are on.

On the canvas, typing / opens the same registry as a quick-insert menu at the cursor — the fastest way to place a resistor without leaving the keyboard.

• Ctrl+. hides every panel — canvas only.
• Ctrl+[ toggles the left panel, Ctrl+] toggles Properties.
• The dock itself can auto-hide, move to any edge, become a full-width bar or a circular dial — Settings → Dock.

The Notebook panel is a filesystem, not a fixed two-level hierarchy. A top-level folder is a notebook (it gets a cover and an emoji); below that, folders nest as deep as you like and hold pages, more folders, or raw uploaded files.

• Drag to reorder or reparent anything.
• Right-click a node for rename, duplicate, colour, export, share and delete.
• Collapsed folders stay collapsed between sessions, and the panel remembers where you were.
• Right-click a page for Export JSON (a per-page backup you can keep) and for its cloud sync toggle — see Sync and multiple devices.
• Delete is immediate and permanent. There is no trash to restore from, so export or back up anything you might want again.

The same panel switches between three views with the filter row at the top: Notebooks (your own), Shared (copies people sent you) and Assignments. Only one is on screen at a time, so the tree gets the full panel height.

Press + in the tree to add a page. The picker offers three top-level choices — Whiteboard, Document and Upload — and Document is the umbrella for every paper-shaped page.

Board

An infinite whiteboard. Pans and zooms without limit, holds every object type, and is where simulations usually live.

Document

A scrolling stack of A4/Letter sheets. Each sheet is a full canvas surface with the same tools, objects and physics as a board — it is paginated, not restricted. Exports to PDF and .docx. Opening an uploaded .docx imports its paragraphs onto these sheets.

Presentation

The same sheet engine laid out as a slide deck: a slide rail down the side, one slide at a time, and a fullscreen Present mode. Imports .pptx (parsing the real slide XML) and exports back to .pptx.

Spreadsheet

A real editable grid, not a screenshot. Imports .xlsx/.xls/.csv on first open and re-exports on demand.

PDF

A reader for any uploaded document — PPT and DOCX are converted to PDF in the browser. Scroll the pages and mark them up with the real pen, with a linked notes pane beside them.

Image

View and annotate an uploaded PNG/JPEG/WebP/GIF/SVG. Ink lives on a transparent overlay; the image itself is never altered.

Web

A browser page you can cache for offline reading and draw on top of. The annotations are stored with your document, not with the website.

• A document’s sheets appear in a filmstrip at the bottom (the page sorter). Drag a thumbnail to reorder, tap to jump.
• Sheets can be resized individually, and each can carry its own background colour.
• A sheet does not pan or zoom internally — it is a fixed piece of paper. Zoom the whole document instead.
• Export PDF and Export .docx sit in the per-page controls at the right of the tab strip; a presentation gets its own control bar under the slide rail.

Drag a file onto the canvas, or use the Uploads panel. Every uploaded file is stored once and referenced everywhere it appears, so inserting the same diagram on ten pages costs one copy of the bytes.

A file in the tree has no renderer of its own — opening it creates a companion page of the right kind and links the two, so opening it again reuses that page instead of re-importing.

PDFs placed on a board render inline through pdf.js and stay crisp at any zoom. Files with a real editor of their own (pptx, docx, xlsx) are attached as proper pages and previewed through that editor.

The page menu offers three outward actions, and all three ship a frozen copy — the original page is never exposed and never edited by anyone else:

Share a copy

Send the page to a person or a room. They get their own editable duplicate.

Create an assignment

Turn the page into work. Every student receives a personal working copy and submits from their own notebook.

Present on a board

Push the page to a paired classroom display. The board loads a temporary copy you can annotate, simulate and rewind live.

Notebook

Your file tree, plus the Shared and Assignments views. The default landing section.

Assistant

The AI conversation. Describe a scene, read the script it produced, add it to the canvas. See The AI assistant.

Components

The palette, grouped by subject package with a domain tab strip and a search box. Click a component, then click the canvas to place it; it stays armed for repeats.

Tools

The utilities that do not earn permanent dock space: the calculator toggle, interactive controls (Slider, Button, Trigger) and quick-insert objects (Formula Table, Graph, 3D Graph, Chart, Code, Measurement).

Uploads

Every picture and file in your workspace as one asset library. Clicking one inserts a reference into the open page.

Library

The institution library — searchable, categorised, favouritable assets published by teachers and admins. Insertion always clones. Students browse read-only.

Properties

The inspector for whatever is selected: geometry, style, parameters and the behavior list. This is where you attach behaviors and where every expression field lives.

Contents

An outline of the current page — a PDF’s embedded bookmarks, a deck’s slide headings. Only appears when the open page actually publishes one.

Select an object and Properties shows everything about it: name, position, size, rotation, colours and stroke, its parameters, and the behaviors attached to it.

• Add behavior lists only the behaviors that make sense for that geometry, each with a one-line description of what it does.
• Every numeric field is an expression field. Type 9.81, or g, or 2*pi*f, or a reference to another object’s live channel.
• Multi-selection edits shared fields at once. Selection actions (align, distribute, group, order) sit at the top.
• On a phone or tablet, opening properties lifts the selected object out of the canvas and floats it above the dimmed page, still live, so you can see what your edit did. Tap the dimmed area to send it back.

Ctrl+N opens a drawer from the right edge: a masonry wall of sticky notes and pasted images, a to-do list, and a month calendar of personal events.

It is deliberately not a rail section. Every rail panel is about the page you have open; this one belongs to you and follows you across every page and notebook.

Ctrl+1, or the toggle in the Tools panel. It floats over the canvas, drags anywhere, resizes from its corner and stays put when you switch pages.

It runs the same maths engine the formula fields use, so sqrt(2), sin(pi/4), 3^4 and log(100, 10) all work. Page variables are deliberately not in scope — this is scratch arithmetic, not part of the document.

Physics events — a collision, a body coming to rest — are announced to screen readers live, and kept in a scrollable log you can read back after a run. The log is collapsed by default; the announcements need no setup.

The bell in the header aggregates shares you have received, assignment activity (new work if you are a student, new submissions if you are a teacher) and room announcements. Read state is tracked per user, per device.

Beside it, the sync indicator shows whether your work has reached the cloud, and opens a popover for device-to-device sync. See Data, storage and sync.

Select · V

Click to select, drag to move, drag a marquee to select many. Handles resize and rotate.

Pen · P

Freehand ink. Stays exactly as drawn unless Ink to Shape is on.

Shaper · S

Draws with 90° elbows — the same as holding Shift with the pen. For wiring diagrams and orthogonal connectors.

Eraser · E

Drag over ink to remove it. Scribble-to-erase is a pen setting.

Text · T

A live formatted text block. Bold, italic, colour, size, lists, links.

Note · N

A sticky note — quick, coloured, resizable.

Formula · F

A maths card that renders and solves. See Formulas and variables.

Graph · G

A live plot of simulation channels and your own expressions.

Grid Table · B

A plain layout table with editable cells and draggable column splitters.

The dock also carries the shape menu, the colour and stroke controls, and (optionally) the transport, a page selector and a Tools/Components launcher — all configurable in Settings → Dock.

Nineteen ready shapes, placed by click-dragging on the canvas: Line/Beam, Circle, Oval, Square, Rectangle, Triangle, Right Triangle, Diamond, Parallelogram, Trapezoid, Pentagon, Hexagon, Heptagon, Octagon, Star, and arrows in all four directions.

A shape placed this way is bare geometry — exactly what the pen would have produced if your hand were perfect. Give it meaning by attaching a behavior.

Double-tap the pen button (or open Settings → Pen feel) for the full pen panel:

Style

The nib character — how the stroke responds to speed and pressure.

Thickness

Base stroke width, and what a mouse or a flat stylus always draws at.

Stability & Smoothness

How much the stroke is filtered as you draw. Higher settles a shaky hand; lower keeps detail.

Sensitivity

How strongly stylus pressure changes the width.

Dot size

Multiplier for single-tap dots, like the dot on an i.

Colour

The swatch palette, plus your own custom colours which stay in the palette.

Scribble to erase

Scrub back and forth over a stroke to delete it, no tool switch.

Ink drawn on a PDF, an image or a web page lives on a real transparent canvas locked to that page — same pen, same undo, same settings as a board. There is no second drawing system to learn.

With Ink to Shape on (Settings → Editor), a freehand stroke that is clearly a circle, oval, square, rectangle, a regular triangle-through-octagon, or a line snaps to that clean geometry.

Ink Annotations is the companion setting: a small scribble next to a component opens the parameter input for it, so you can write a value where you would have written it on paper.

The Tools panel arms an object; you then click the canvas to place it. Esc stops. The same set is reachable from the / menu on the canvas and from global search.

Formula Table

A spreadsheet-style table whose column headers can be formulas.

Graph

Live plotting of channels and expressions.

3D Graph

Surface plots — explicit sin(x)*cos(y) or implicit x^2+y^2+z^2=25.

Chart

Bar, line, area, scatter and pie over a small data grid.

Code

The SimScript IDE — build a scene by typing it.

Measurement

Click-drag across the canvas to leave a dimensioned measurement.

Slider

Drag a value and watch the scene respond. Binds to a page variable or any object parameter.

Button

Runs an action on click: set, toggle or step a value.

Trigger

Watches a value and fires an action when a condition is met.

• Undo and redo are in the header as buttons as well as on Ctrl+Z / Ctrl+Shift+Z, so a tablet without a keyboard can still reach them.
• Copy, cut, paste and duplicate work across pages and across notebooks, carrying behaviors and parameters with the object.
• Everything the AI does goes through the same history — an auto-applied script is as undoable as anything you typed.

Text

A formatted block that is WYSIWYG all the time — bold, italic, underline, colour, size and lists are style ranges over the text, never markdown characters you have to look at. The line with the caret renders exactly like every other line.

Note

A sticky note: coloured, resizable, deliberately small.

Picture

A raster image placed as one object among others — drag, resize and select it like any shape. Different from an image page, which is a whole tab for viewing and annotating one image.

File

A document embedded in a board. PDFs render inline via pdf.js; pptx/docx/xlsx are attached as their own page and previewed through that page’s real editor.

Formula

Write f(x) = x^2 + 3*x, 10<x<20 (bounds optional; several variables give partials). Select it and the calculus actions — d/dx, ∂/∂x, ∫dx, Laplace, Fourier — appear in Properties, and the worked step-by-step solution renders inside the card.

Formula Table

Excel-style. Each column header is either a plain name (x) or a formula (z = x + y), evaluated against the page scope in declaration order, so a column can reference one to its left. The last row is a Sum/Avg/Min/Max summary.

Grid Table

A layout table: editable cells, add/remove rows and columns, draggable column splitters. No maths, just structure.

Graph

Plots live simulation channels from one or many objects, and your own expressions against the page scope, on the same axes. Custom axes, scales, reference lines and phase portraits (plot one channel against another rather than against time). With no series bound, it plots your formulas over the x range like a graphing calculator.

3D Graph

The surface-plot counterpart. Two input styles on one field, auto-detected: explicit sin(x)*cos(y) gives a height field, implicit x^2 + y^2 + z^2 = 25 is root-found and rendered as two caps. A graph can also reinterpret its first three plotted panels as X/Y/Z for a 3D trajectory.

Chart

Bar, line, area, scatter and pie over a small labels-plus-series grid — the spreadsheet-simple counterpart to Graph. Switching chart type keeps the same data; “stacked” is a modifier on bar and area, not a separate chart family.

Truth Table

Pick which of the circuit’s inputs and outputs to tabulate. Every input combination is then actually simulated on the real board — no symbolic shortcut — and the results laid out as a table.

Cash Flow

An engineering-economics timeline: arrows up for inflow, down for outflow, height proportional to amount. The spec (investments, annuities, salvage, MARR) is edited in Properties, and PW/FW/AW/IRR/CR/BC sit above the diagram. Hover the timeline for the compounded value at that instant.

Measurement

A persistent dimensioned line between two points on the page, for annotating a drawing with real distances.

Each domain has a System component: a labelled frame that sits behind its contents and groups them into one named subsystem. Use it to say “this rectangle of the page is the power stage” without changing how anything inside behaves.

1. 1Open Components in the left rail.
2. 2Pick a domain tab, or type in the search box to search every domain at once.
3. 3Click a component — it arms.
4. 4Click the canvas to place it. It stays armed, so you can place a row of resistors without going back to the panel.
5. 5Esc disarms and returns you to Select.

Packages can be switched off in Settings → Packages if a subject is noise for you, and an institution can license a subset — a component you do not have access to simply is not in the palette.

This inventory is generated from the same registry the palette reads, so it is always the current one.

1. 1Select the object.
2. 2Open Properties in the left rail.
3. 3Press Add behavior and pick from the list — only behaviors valid for that geometry are offered.
4. 4Fill in its parameters. Every one accepts an expression, not just a number.

An object can carry several behaviors at once. A motorised wheel is a circle with both a Rigid Body and a Motor; a charged ball is a Rigid Body plus a Charge. Remove a behavior and the object reverts to being a drawing — nothing else about it changes.

Generated from the behavior registry — the same table the Add Behavior menu, the world builder and the AI importer read. A few are registered but await their solver; those are marked.

Pressing Play compiles the page exactly as drawn into one running world. Nothing is regenerated from a template, and nothing about your scene is modified — Reset simply discards the running world.

• Rigid-body physics steps at a fixed 120 Hz, independent of your display rate.
• Circuits are solved every step alongside it.
• Parameters that are expressions are re-evaluated every frame against the page scope.
• Graphs sample at a lower rate on purpose — plotting at 120 Hz would cost more than it shows.

Bodies have mass, friction and elasticity, collide (including against concave meshes built from your own sketches), and can be stacked, linked and driven. Springs, ropes, rods, dampers, hinges and motors connect them.

Gravity g is a page variable like any other. Set it to 1.62 and your experiment is on the Moon; sweep it with a slider and watch the period of a pendulum change while it swings.

A Rigid Body also carries three tracers you can switch on in Properties: motion vectors, path trail and force arrows. A Reference Point is a near-massless body with the trail already on — an observer you can pin to something to see where it goes.

Symbol terminals and drawn wires are resolved into nets, then each step runs Modified Nodal Analysis — real KCL/KVL and Ohm’s law, with companion models for capacitors and inductors, iterated piecewise states for diodes, LEDs, BJTs and MOSFETs, and the op-amp as a constrained source.

• Wires bond at their endpoints within a snap radius. Two components merely overlapping do not conduct.
• Ink counts: a pen stroke that touches two terminals is a wire, and current animates along it.
• Current is drawn twice — conventional flow one way, electron drift the other — and the animation speed tracks the actual amps.
• Meters are components: Voltmeter, Ammeter, Wattmeter and Probe read the live solution.

Gates, flip-flops, latches, multiplexers, decoders, adders, comparators, counters, shift registers and 7-segment displays are solved as a fixpoint pass every step, alongside the analog solver.

• Every pin shows its live 0 or 1.
• Inputs are clickable while the simulation runs — toggle one and watch it propagate.
• The Clock component drives sequential logic at a frequency you set.
• Drop a Truth Table on the page, pick the inputs and outputs, and it simulates every combination for real.

Geometric optics

Light sources, thin lenses, mirrors and screens — rays traced through the layout you drew.

Diffraction and interference

A source, a slit mask and a screen produce a Huygens–Fresnel phasor sum over the open apertures at real dimensions. The single-slit envelope and the cos² fringes come out of the wave equation, not out of a picture of one. Change wavelength, gap or spacing and the pattern responds as theory says it should.

Photons

In Play, single photons land stochastically at Born-rule positions, so you watch randomness accumulate into the interference pattern.

Waves and EM

Plane-wave sources, boundaries, media interfaces and transmission lines.

Quantum

Particle-in-a-box eigenstates and rectangular tunnelling barriers, solved from the Schrödinger picture with live parameters.

Objects publish channels — a mass streams x, y, vx, vy, angle, angular velocity and kinetic energy; a resistor streams V, I, P; a logic probe streams its level. Each object only offers the channels it can genuinely produce.

1. 1Find the probe dot in the header of anything that consumes values — a graph, a variable, a slider.
2. 2Press it and drag. A dotted arrow follows your pointer.
3. 3Release over the object you want to read. A chip at the arrowhead lets you pick which channel.

What gets written is an ordinary parameter, so the same binding is visible and editable in Properties as text: [Mass 1(vy)]. You do not have to press Play first — channels are known before the simulation has ever run.

Anywhere the app asks for a number, it will also take an expression: a mass, a spring constant, a resistance, a motor speed, a force field, a graph axis, a table column.

• Arithmetic and powers: 2*pi*r, 3^4, (a+b)/2.
• Functions: sin, cos, tan, sqrt, log, exp, abs, min, max and the rest of the standard library.
• Page variables by name: g, k, m.
• Live channels of other objects: [Mass 1(vy)].

Autocomplete in an expression field offers the variables and channels actually available on that page, so you can discover a binding from the field you are editing rather than having to go and build a variable first.

A page has its own set of named variables, with spreadsheet semantics: definition order does not matter. Dependencies are worked out from the expressions themselves and solved in the right order, so you can define ω = sqrt(k/m) above the line that defines k.

A circular definition becomes an inline error on the offending variable — it never throws and never stops the page.

Write f(x) = x^2 + 3*x in a Formula object and it renders as typeset maths. Add bounds — , 10<x<20 — to restrict it. Several variables give partial derivatives.

Select the card and Properties gains the calculus actions: d/dx, ∂/∂x, ∫dx, Laplace and Fourier. The result appears as a worked, step-by-step solution inside the card, not just a final answer.

Settings → Math controls how every number in the app is displayed, with a live preview at the top of the tab:

Decimal precision

0–8 digits after the point.

Number notation

Auto switches to exponents for very large or small values, Plain never does, Scientific always does, and Engineering locks exponents to powers of three.

Angle units

Degrees or radians for display. The solver always works in radians internally.

Unit labels

Append cm, N, m/s and friends to readouts.

Thousands separator

Digit grouping, 1,234.5.

Open Assistant in the left rail and describe what you want — “a projectile hitting a spring on an incline”, “a half-wave rectifier with a smoothing capacitor”, “plot the velocity of the falling mass”.

The assistant replies with a SimScript — the same scene-building script you could have typed in the Code object yourself. It produces exactly the primitives and behaviors a person places by hand; there is nothing it can build that you cannot.

It is a real conversation. Every turn keeps its script, so you can compare two attempts, re-run an earlier one, or copy a script into the Code IDE and edit it.

Manual

The script lands in the thread and waits. You read it, then press Add. Nothing touches your canvas until you say so. This is the default.

Auto

A verified script executes the moment it arrives. Faster when you are iterating.

Auto is only reasonable because of the verifier: a script reaches the canvas only after passing every static check, so “just do it” cannot quietly produce a broken scene. Both modes run identical generation — the only difference is who presses the button. And an auto-applied script is undoable like any other edit.

• Ask for a scene and you get a script to add.
• Ask a question about physics or about the page and you get an explanation, not a scene.
• Ask for a change to what is already on the page and it plans an edit against the existing objects rather than starting over.

Which of these happens is decided from your wording, so you do not have to pick a mode first.

• The assistant runs against a local model. Your prompts and your scenes stay on the machine serving the app.
• If no model is available, the panel says so rather than silently failing — a machine with no local model is a supported configuration, the notebook does not depend on the AI for anything.
• Output quality depends on the model. Complicated multi-part requests are more reliable split into two or three smaller ones.
• Students do not get the assistant. That is deliberate: the goal is that students build the systems themselves.

The Code object is a small but real IDE for SimScript: syntax highlighting, line-accurate diagnostics (reserved words, unknown kinds, unclosed brackets or strings) marked in the gutter, and snippet buttons that insert a ready-made line at the cursor.

Anything the assistant produces is plain SimScript you can paste here, read and change. It is the same path to the canvas either way.

Place a DSA Lab from the palette (or the Tools panel) and you get a C++ editor on the left and a live visualisation on the right. The code is re-interpreted on every edit into a step-by-step trace, and the transport replays it: the current line stays highlighted in the editor while memory, pointers and the call tree animate beside it.

It is a teaching-subset interpreter, not a full C++ compiler. It covers what an algorithms course actually writes: scalars, arrays including 2D, pointers and references, struct/class with fields, methods and constructors, new/delete, vector, stack, queue, pair, map, set, priority queue, deque, std::string, cout, control flow and recursion.

Memory

Every variable is a block with its name, value and a real address. Arrays are consecutive cell strips with indices, so pointer arithmetic is honest. Heap allocations are highlighted, pointers are drawn as arrows between the actual cells, and the most recent write glows.

Call tree

Every function call is a node; recursive calls branch with their own parameters, so fib(5) literally grows into a tree and each node shows its return value once it finishes.

Tree

When your program has a struct with two self-referential pointer fields — Node* left; Node* right;, whatever you named them — it is drawn as an actual tree diagram instead of a tangle of boxes. Covers BST, AVL and heap-as-tree.

Graph

A vector<vector<int>> adjacency list anywhere in memory — including nested inside a class Graph — is drawn as a node/edge diagram.

Analysis

Operation counts measured from the actual run, the inferred recurrence relation for each recursive function, and a heuristic Big-O estimate. Honestly labelled: these are measurements of this execution, not proofs.

Your institution is the tenant; you belong to exactly one and have exactly one role. Room Board is not a person — it is the account a physical classroom display signs in with.

Students deliberately get fewer shortcuts — no assistant, no library publishing — because the point of the platform is that they build the systems themselves.

Any page can become an assignment. The flow, end to end:

1. 1A teacher opens a page and chooses Create assignment, setting a title and a due date.
2. 2Every student receives their own working copy in their Assignments view — the original teaching page is never handed out.
3. 3Students work in their copy with the full notebook, then submit from it.
4. 4The teacher sees a live dashboard: opened → in progress → submitted → reviewed, with feedback flowing straight back.

Due soon surfaces on your home screen, and assignment activity reaches you through the notification bell.

Teachers get an insights view over their assignments: overall stats, a class-wide completion-rate trend, a per-assignment breakdown table, and per-student performance and trend. It aggregates the assignments and submissions you already have — nothing extra is collected to produce it.

A shared bank of pages and assets for the whole institution. Search it, browse by category, favourite what you use often, and insert with one click — insertion always clones, so the library copy cannot be edited by accident.

Teachers and admins publish to it; admins approve. Students browse it read-only.

1. 1The classroom display signs in as a board account and shows a rotating QR code.
2. 2A teacher scans it with their phone and picks any page from their notebook.
3. 3The board loads a temporary copy. Annotate it, simulate it, rewind it — the original teaching material is never touched.
4. 4The teacher’s device can drive the board remotely, with the pointer mirrored live so the room can follow.

Present mode also works on its own for a fullscreen slideshow of a presentation page, with viewport sync and remote control.

Sharing sends a frozen copy to a person or a room. The recipient finds it in their Shared view and gets a notification. Because it is a copy, they can change it freely and you never lose your original — and if you change yours afterwards, theirs does not move under them.

Admins get /admin: managing people and their roles, rooms and their members, board accounts, library approvals and institution settings such as name, logo and accent colour.

Your account menu at the top right → Settings. On a phone it opens as a grouped iOS-style list you drill into; on desktop it is a window with a sidebar, searchable from the box at the top.

General

Your name, email, role and institution, and signing out.

Appearance

Theme (light, dark, dim, midnight, sepia, solarized, high contrast and several tinted themes, or follow the system), accent tint including a custom colour, and interface motion — bouncy springs, smooth transitions, or off for reduced motion. Also Focus object on edit, the touch behaviour that lifts a selected object out of the canvas while you edit it.

Interface

Text and scaling: interface scale (panels, docks, toolbars), canvas object scale (text inside tables, graphs and code blocks on the page), a separate sidebar text size, and panel letter spacing.

Dock

Where the tool dock lives and what it looks like. Fixed to an edge (bottom, top, left, right) or freely draggable; compact or extended layout; and in extended mode you can embed the transport, the Tools/Components launcher and the page selector inside it. Appearance options cover container style (floating island, full-width bar, or circular dial), shape, colour treatment, size and auto-hide.

Editor

Canvas and grid: scrolling axis (free, vertical or horizontal), grid style (dots, ruled, graph or none) and cell size. Editing behaviour: Ink to Shape, Ink Annotations and disabling double-tap zoom.

Files and links

Sync preferences per content category, a storage browser showing usage by type with a delete-capable tree, and full local backup and restore.

Hotkeys

Every keyboard shortcut, rebindable. See Keyboard shortcuts.

Gestures

Touch feel: pinch sensitivity, hold-before-drag delay (so a quick swipe still scrolls), the tap-versus-drag distance threshold, and palm rejection radius.

Math

Precision, number notation, angle unit, unit labels and thousands separator, with a live preview.

Packages

Turn subject component packages on or off so the palette only carries the subjects you teach or study.

Pen feel

The full stylus panel — style, thickness, stability, smoothness, pressure sensitivity, dot size, colour palette and scribble-to-erase.

Simulation Engine

Information about the solver driving Play.

Privacy

The full privacy policy as shown at first sign-in, the analytics opt-in, and a link to re-read the terms.

About

Version, update check and credits.

Your notebook is stored on the device first — that is what lets the app keep working on a bad connection or none at all. What leaves the device is then a choice you make per page, not an automatic upload of everything.

Settings → Files and links → Storage shows what is actually taking up space: a usage-by-type breakdown and a tree you can delete from, covering documents and PDFs, presentations, spreadsheets, images, boards and everything else.

• The header indicator shows whether your work has reached the cloud.
• Sync preferences in Settings → Files and links let you choose which categories of content travel at all.
• Individual uploaded files have their own sync toggle, independent of the page.
• Device-to-device sync moves a workspace directly between two of your machines.
• SIMBLIP installs as an app on desktop and mobile, with offline support — add it to your home screen or install it from the browser’s address bar.

Settings → Files and links → Backup produces a single zip of everything this account has on this device: the notebook tree, every page’s content, spreadsheet grids and the bytes of every locally stored file. Re-importing the same zip restores it, or moves you to a new device.

• A document page exports to PDF and to .docx.
• A presentation exports to .pptx.
• A spreadsheet re-exports to .xlsx.
• An annotated PDF exports with your ink.
• Any page can be shared as a copy to a person or a room.
• Right-click any page in the tree for Export JSON — a portable copy of that one page.

The full policy is in Settings → Privacy, identical to the text shown at first sign-in. Analytics is opt-in and can be turned off there at any time. AI prompts go to a local model, not to a third-party service.

Nothing happens when I press Play

Objects with no behaviors are drawings. Select one, open Properties, and attach a Rigid Body — or place a component from the palette, which comes with its behaviors already attached.

My spring is not pulling on the mass

Constraints attach by touching. Make sure the spring’s endpoint actually overlaps the body. If it finds nothing, it anchors to the world instead.

My circuit reads zero

Wires bond at their endpoints within a snap radius, and overlapping bodies do not conduct. Check that each wire end lands on a terminal, and that the loop is actually closed — most circuits also need a Ground.

The tools are drawing on the wrong page

In a split view, the dock follows whichever pane you last clicked into. Click the pane you mean first.

My pen strokes keep turning into shapes

That is Ink to Shape. Turn it off in Settings → Editor.

A shortcut does nothing

Some are conditional — stepping only works while paused, the eraser only while editing. Check the condition next to it in the shortcuts list, and check nothing has rebound it in Settings → Hotkeys.

I deleted a page by mistake

Deletion is permanent — there is no trash. If the page had cloud sync enabled and another device has not synced since, that device may still hold a copy. Otherwise the recovery route is a backup zip taken earlier. Use Export JSON on pages you care about.

The AI panel says it is unavailable

The assistant needs a local model on the machine serving the app. Everything else in the notebook works without it. Students do not get the assistant at all.

Your account menu → Report a bug. It is two fields: what happened, and what you expected. Your browser, OS, viewport and the route you filed it from are captured automatically — those are exactly what makes a report reproducible and exactly what nobody remembers to include.

SIMBLIP is licensed to institutions rather than to individuals. If your school or university is not provisioned yet, contact licensing from the landing page. If you already have an account and cannot sign in, your institution’s admin manages accounts from the admin console.