How many bits per pixel are you assuming, and are you imagining the red pixels are vertical neighbors with corresponding red pixels above and below, etc.?
Should be easy to do on my phone: https://itch.io/post/15723528
Should be easy to do on my phone: https://itch.io/post/15723528
Maybe I should try 2bpp. Or some HSL where I can clamp L.
Edit: Oh yes, it's interesting at 2bpp!