#define wall_width 16
#define wall_height 16
static char wall_bits[] = {
   0xff, 0xff, 0xff, 0xff, 0x03, 0xc0, 0xab, 0xca, 0x53, 0xd5, 0xab, 0xca,
   0x53, 0xd5, 0xab, 0xca, 0x53, 0xd5, 0xab, 0xca, 0x53, 0xd5, 0xab, 0xca,
   0x53, 0xd5, 0x03, 0xc0, 0xff, 0xff, 0xff, 0xff};
