#define rock_mask_width 13
#define rock_mask_height 13
static unsigned char rock_mask_bits[] = {
   0x80, 0x01, 0xf0, 0x03, 0xfc, 0x03, 0xfc, 0x07, 0xfe, 0x0f, 0xff, 0x0f,
   0xff, 0x1f, 0xff, 0x1f, 0xfe, 0x1f, 0xfe, 0x1f, 0xfc, 0x0f, 0xf8, 0x0f,
   0x70, 0x07};
