The computer program for the game uses a coordinate system to keep track of the locations of Mary's boat, her lure, and the fish. The game is programmed such that fish within 7 units of the lure can attempt to bite it; other fish can't attempt to bite it. The units of the coordinate system are in meters. (3,−3) is the location of Mary's lure. (7,3) is the location of Fish A (-4,-2) is the location of Fish B. (-2,1) is the location of Fish C.