Oh, I see. The rotation control is kind of strange. Rather than have it control the momentum of the spin, it would be more natural to have the left/right arrows

Oh, I see. The rotation control is kind of strange. Rather than have it control the momentum of the spin, it would be more natural to have the left/right arrows first stop the automatic rotation, then simply rotate at fixed-size intervals. Play/pause/left/right buttons may work even better.