#define wall_width 16
#define wall_height 16
static char wall_bits[] = {
   0xff, 0xff, 0x01, 0x80, 0x55, 0x95, 0xa9, 0xaa, 0x55, 0x95, 0xa9, 0xaa,
   0x55, 0x95, 0xa9, 0xaa, 0x55, 0x95, 0xa9, 0xaa, 0x55, 0x95, 0xa9, 0xaa,
   0x55, 0x95, 0xa9, 0xaa, 0x01, 0x80, 0xff, 0xff};
