#define grey_width 16
#define grey_height 16
static char grey_bits[] = {
   0x11, 0x11, 0x44, 0x44, 0x11, 0x11, 0x44, 0x44, 0x11, 0x11, 0x44, 0x44,
   0x11, 0x11, 0x44, 0x44, 0x11, 0x11, 0x44, 0x44, 0x11, 0x11, 0x44, 0x44,
   0x11, 0x11, 0x44, 0x44, 0x11, 0x11, 0x44, 0x44};