import numpy as np


def saveAsPrg(fn, address, data):
    fo = open(fn, "wb")
    header = np.array((address & 255, address / 256), np.uint8).tostring()
    fo.write(header)
    fo.write(data)
    fo.close()


y, x = np.indices((200, 320))
yy = (y * 2 + 1 - 100) ** 2
xx = (x * 2 + 1 - 160) ** 2
r = (xx + yy) ** .5
bits = (r / 6).astype(np.int) % 2

bits = bits.reshape((25, 8, 40, 8))
bits = bits.transpose((0, 2, 1, 3))
bits = np.sum(bits * [128, 64, 32, 16, 8, 4, 2, 1], axis=3)
if 1:
    bits[-1, -1, :] = [
        0xe8,
        0xd4,
        0xb2,
        0x71,
        0x8e,
        0x4d,
        0x2b,
        0x17,
    ]

data = bits.astype(np.uint8).tostring()
saveAsPrg("bmp.prg", 0x2000, data)
open("bmp.bin","wb").write(data)