The ending was in George Clayton Johnson's script but not in A Game of Pool (1961), of which this was a remake.
Rotation, sometimes called rotation pool or 61, is a pool game, played with a pocketed billiards table, cue ball, and triangular rack of fifteen billiard balls, in which the lowest-numbered object ball on the table must be always struck by the cue ball first, to attempt to pocket numbered balls for points.