The Explode Game
Before the 1995 GUI Festival in Glasgow, a workshop on graphical user-interface toolkits and functional programming, a number of programming challenges were distributed to the participants.
One of the challenges was to implement The Explode Game.
In The Explode Game, two players take turns placing stones, or atoms, in the squares of a board. A player can not place atoms in a square that already contains atoms from the opponent. When a square is full, that is, contains as many atoms as it has neighbours, it explodes, sending one atom to each neighbour. All atoms of the invaded square change color to the invading atoms color. Invaded squares may become full and explode in turn. When the board has settled, a new move can be entered. When the board starts to get full of atoms, placing a new atom may cause an infinite chain reaction. When this happens, the game is over and the player who caused it is the winner.