Turing wants to play the following game on his computertm. the computer memory is unbounded and there is no time limit for finishing the game. the game board is the set of points in the plane with integer coordinates and time moves in discrete integer steps. there is a hidden stealth aircraft piloted by church. turing does not know church’s location, his speed or his direction of motion. the speed and direction of motion do not change throughout the game. the speed is a natural number and the direction of motion is either "up", "down", "left" or "right". for example, church could start at (2,3), have speed 7, and move right. then at step 0 he is at (2,3), at step 1 he is at (9,3), at step 2 he is at (16,3), and so on. at every step, turing gets to zap a point: he enters the coordinates and if church is at that point, at that time step, turing will destroy church. of course, there is no point zapping a position before church gets there or after he leaves. give a (deterministic) strategy or scheme for turing so that he is guaranteed to get church at some finite stage.