Automatic Optical Illusions Using Python and OpenCV

Something like:

    width, height, _ = bw_img.shape
    pixels = int(width * height * .5)
    xs = np.random.choice(width, pixels)
    ys = np.random.choice(height, pixels)
    bw_img[xs,ys,:] = img[xs, ys, :]

I mean, it's just how our eye+brain work indeed. You can make it "better" by dezooming on the images, or "worst" by zooming in, which is just as expected.

It doesn't really seem far from other techniques for image compression, just a less good version of those ?

This reminds me of the old King of the Hill episode where Dale says "If you want, I can show you how to make a bomb out of a roll of toilet paper and a stick of dynamite."