def overlap(self, x1, y1, x2, y2, r=<NUM_LIT:5>):
if abs(x2-x1) < r and abs(y2-y1) < r:<EOL><INDENT>return True<EOL><DEDENT>else:<EOL><INDENT>return False<EOL><DEDENT>
Returns True when point 1 and point 2 overlap.

        There is an r treshold in which point 1 and point 2
        are considered to overlap.