Perceptual Puzzle #12- Staying In Place -
The image below shows a pool rack with 15 billiard balls which fit perfectly within the rack
(i.e. there is no extra space for any of the balls to move).
Note that the rack above is slightly smaller than an actual/standard pool rack in which there is a
small amount of space between the rack and the balls.
What is the maximum number of balls that can be removed from the rack such that the remaining balls
are still immobilized (i.e. unable to move)?
Do you have a suggestion
for this puzzle (e.g. something that should
be mentioned/clarified in the question or solution, bug, typo, etc.)?