#define rock_width 13
#define rock_height 13
static char rock_bits[] = {
   0x00, 0x00, 0x70, 0x00, 0xfc, 0x01, 0x3c, 0x04, 0x0e, 0x08, 0x0f, 0x08,
   0x0f, 0x10, 0x03, 0x10, 0x02, 0x10, 0x02, 0x10, 0x04, 0x08, 0x18, 0x07,
   0xf0, 0x01};
