A measurement-grade deterministic mechanics platform: fourteen verified apparatus — orbits, collisions, buoyancy, the double-pendulum chaos gateway — each one you can run, scrub, branch, and measure.
The DIOPTRA optical bench: place lenses and mirrors, trace rays through them, and watch real and virtual images form as you move objects and change focal lengths.
An interactive truss workbench: build a structure, load it, and read the member forces — tension and compression resolved at every joint in static equilibrium.
Drag the boost and watch simultaneity tilt. Worldlines, light cones, the twin trip, and the barn–pole squeeze — with every spacetime interval invariant to 12 decimal places, verified on every commit.
Spin a body about each of its three principal axes: two spins are stable, the middle one flips over and over. Energy and angular momentum conserved to machine precision; the flip period is verified against the Jacobi-elliptic closed form.
Launch a projectile at a target under Earth, Moon, or Mars gravity: tune the angle and speed and read the parabola — the classic first lab.