A mathematical billiard table is in the form of a rectangle with integral sides, and just four pockets, one in each corner. A ball shoots out of one pocket at angles of 45° to the sides. Will it bounce round the table for ever, or end up in one of the other pockets?
REVEAL THE ANSWER
It will definitely end up in one of the other three pockets. It is not possible for it to bounce for ever or end up in the pocket it started from.