ONBOARD
while ((ONBOARD(ts.x, ts.y)) &&
if ((--ts.hits > 1) && (ONBOARD(ts.x, ts.y)) &&
#define POSSIBLE(x, y) (ONBOARD(x, y) && !hits[COMPUTER][x][y])
if (ONBOARD(xend, yend))
if (!ONBOARD(xend, yend))
if (ONBOARD(x1, y1))