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Ball in a spinning ring
Why Spinning the Ring Changes Nothing
Two balls in a spinning ring, explained. Every bounce is elastic, so the balls never slow down. The spin changes nothing about the bounces — a frictionless wall only moves along itself, so it cannot push a ball in or out. All the rotation does is carry the hole around; the balls stay low, so their chance comes once per revolution. The hole grows each round, and a ball gets out only when the whole of it fits through the gap. This run was picked from 500 so that the first escape lands in the final seconds.
The rule
Balls bounce inside a spinning ring with a gap that grows. The spin only carries the gap around.
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