#define spiral_width 16
#define spiral_height 16
static char spiral_bits[] = {
 0xfe,0xff,0x02,0x80,0xfa,0xbf,0x0a,0xa0,0xea,0xaf,0x2a,0xa8,0xaa,0xab,0xaa,
 0xaa,0xaa,0xaa,0x2a,0xaa,0xea,0xab,0x0a,0xa8,0xfa,0xaf,0x02,0xa0,0xfe,0xbf,
 0x00,0x80};