Pebbling a Chessboard: An Interesting Math Puzzle

Numberphile pays a visit to Zvezdelina Stankova, Visiting Professor and Director of the Berkeley Math Circle, to look at an interesting puzzle you can try for yourself. To “free the clones” from the three squares in the corner of a chessboard following a simple set of rules. This is one of those puzzles that, at first glance, looks pretty straightforward and seems solvable in a few moves.