4 ms·

Reminds me of the blue-eyed islanders puzzle. http://www.xkcd.com/blue_eyes.html http://www.xkcd.com/blue_eyes.html

• jules 16y ago
  That's a similar puzzle. Maybe it's because I solved the homework puzzle first, but the blue eyes puzzle is much much easier. You might want to try to solve that first ;) The cool thing about the blue eyes puzzle is that you can solve it without a computer or pen and paper.