Animated, interactive vector explainers and drills — each one a single file that carries everything it needs.

Every piece below is an artefact: one HTML file holding the document, the evaluator and the drawing code. Save it, open it with no network, put it behind a login or beside a lesson — it behaves the same. The maths is not baked into the picture; the picture is drawn from the maths, by the same evaluator the editor uses.

Open the editor Runs entirely in your browser. Made for a desktop or a tablet.

Pieces

Lever & load

A beam on a fulcrum. Effort and advantage are read from the distances, so the numbers cannot disagree with the drawing.

  • Drag the load or the effort along the beam; slide the mass.
  • The effort in newtons and the advantage follow the geometry.
Open Explainer 1.2 MB

Tangent & slope

A sine curve with a tangent at a movable point. The slope is the derivative of the very expression the curve is drawn from.

  • Drag the point along the curve.
  • Drag the amplitude handle; the curve, the tangent and the slope all follow.
Open Explainer 1.2 MB

Finger & table

A fingertip meeting a table, then nine decades of zoom down to the electron clouds that keep the two apart. The motion is authored, not simulated.

  • Press Play and let it run through its three states.
  • Read the scale bar — it is measured from the view, not typed.
Open Explainer 1.2 MB

Quadratic drill

Drag two handles onto the roots of a quadratic, then check the answer. A fresh task each time, marked against the curve rather than against a stored answer.

  • Press Practice, drag both handles to the roots, then Check.
  • Take Next for another task and watch the score.
Open Drill 1.2 MB

Double pendulum

The one piece that cannot be keyframed. Its equations of motion are written in the ordinary grammar and stepped, and its energy is checked as it runs.

  • Press Run, then Rewind and run it again — the same start gives the same run.
  • Nudge a starting angle first, and the two paths part company.
Open Simulation 1.2 MB

Bracket, in section

A technical drawing on A5 paper at 1:2 — hidden and centre lines, hatching by material, and dimensions that read their own geometry.

  • Read the dimensions — they quote the part, not the line on the page.
  • Open Checks: hatch angles, line weights and a black-and-white sheet are all verified.
Open Drawing 1.2 MB

What you are looking at. Each piece is a typed parametric document — quantities with units, figures, controls, states and checks. The editor, the verifier and the file you open here all run one evaluator, so a piece cannot mean one thing while it is being written and another once it is published.

Why the files are large. An artefact carries its own runtime, so it is about 1.2 MB regardless of how small the drawing is. That is the price of a file that still works in five years with nothing else installed.

These are working examples, not a course. They exist to exercise the editor, and each is the smallest piece that tests something the design claims.