Video explains the following brain teaser: One-hundred perfect logicians are blindfolded and each has their forehead painted blue. They all enter a room with the lights off, sit in a circle, and the lights are turned on. Each logician can see the foreheads of the other 99 people, but not his own. The lights are then turned off, and anyone who has deduced that their own forehead is painted blue leaves the room. The lights are turned on again, and the process continues. Given that every logician has their forehead painted, the problem question is: What happens, when, and why? The solution is presented in a following video. [7:25]