Squash and stretch: how a ball comes alive
The single most important principle, with the simplest possible example.
March 2026 · 1 min read
A falling ball flattens a little on impact and stretches a little as it springs up. This is squash and stretch. Without it, the ball looks like a hard stone; with it, rubbery and alive.
There is one golden rule: the object’s volume must stay constant. When the ball flattens it must also widen, as if the amount of stuff inside has not changed. Break this and the object seems to pop or deflate.
