Since we talked about logical puzzles recently, here’s one for you to try. The International Mathematical Union has recently announced that its permanent office will be based at the Weierstrass Institute in Berlin. Two clicks from the front page, and you get to The Mathematical Community in Berlin, featuring photographs of 12 of the distinguished mathematicians who supported the bid.
Look at these photographs. Can you see a pattern?
For comparison, here’s a photo of the IMU Executive Committee.