Bouncing Ball

Bouncing Ball — The classic analog-computer demo (Telefunken shipped it to sell integrators): two integrator chains under constant gravity, a comparator that flips the vertical velocity at the floor with a restitution loss, and wall reflections for the drift. The scope draws the familiar train of shrinking parabolic arcs; when the bounces decay away the machine re-kicks the ball, as the unattended trade-show loop did. Floor hits blip at a pitch set by impact speed (once audio is unlocked by any interaction). Knobs: gravity, restitution, drift. Try Persist to paint the full arc family.

y'' = −g, bounce: v ← −e·v at the floor

It opens running, on the model selector, with its own knobs. Rotate it by dragging, zoom with the wheel, and turn the parameters to see what the figure does when the system changes.