wolf and sheep on a chess board. the wolf is red and the sheeps are blue. the wolf starts the game on one side of the board, he always makes the first move and can move diagnostically forward or backwards. there are 4 sheeps who start the game on the 4 black pieces on the other side of the board and can move only diagnostically forward on their turn, one sheep every turn. the sheep's goal is to prevent the wolf's ability to move. the wolf's goal is to reach the sheep's side. none of the pieces can "eat" each other or move to a square where a sheep or a wolf is already located. the valid moves are highlighted in green for the player to pick from. the pieces are moved with the computer's mouse.