return;
return 0;
static void island_try(int x, int y, int u, int v, int *run) {	int n, m;	n = x + y * ntiles_x;	m = u + v * ntiles_x;	if (tile_has_diff[n]) {		(*run)++;	} else {		*run = 0;	}	if (tile_has_diff[n] && ! tile_has_diff[m]) {		/* found a discontinuity */		if (tile_tried[m]) {			return;		} else if (*run < grow_fill) {			return;		}		copy_tiles(u, v, 1);	}}