Bishop vs Aliens
A lone chess bishop finds himself standing on the (zero-based indexing) square (x, y) of a curious m * n chessboard floating in outer space, covered with completely frictionless magic ice. This board is not necessarily square, but can be any rectangle of integer dimensions. The board is surrounded from all sides with bouncy walls similar to an air hockey table. Some of the squares on the board contain aliens that make game over man for anyone who enters that square.
The bishop can initially propel himself to any of the four diagonal directions. After this initial impulse gets him going, the bishop can no longer control his movements on the frictionless ice, but will keep sliding towards whatever end the present direction vector and bouncing from the walls take him. It is even possible for the...
