# What is the answer to this Bongard problem?

Source: Bongard problem #112 by Douglas R. Hofstadter

I've scoured the internet, and I've yet to find an answer to this puzzle. (edit: It has been given the title of "Hardest Bongard Problem" presented on like 50 sites, without solution)

In a Bongard problem, you are given 12 pictures, 6 on one page and 6 on the other. The pictures on the left page conform to a rule, and the pictures on the right page conform to a different rule. Furthermore, a picture on one side cannot conform to the rule on the other side. The goal is to determine the rules.

You can find plenty of examples here: http://www.foundalis.com/res/bps/bpidx.htm

• Reminds me of the hour/minute/second hands on a clock. Aug 30, 2016 at 21:41
• Ironically enough, the very same site you linked to has the solution -- but I'll let more people work on it, it's a deceptively simple rule.
– ffao
Aug 30, 2016 at 21:55
• Really? It doesn't seem to me that his site contains a list of solutions to the problems. Aug 30, 2016 at 21:58
• I've seen a solution elsewhere on the internet (I forget where). I find the rule rather an unnatural one and don't feel too bad about the fact that I didn't solve it before getting bored and looking at the answer :-). Aug 30, 2016 at 22:20
• Well maybe I am unnatural; I know I'm difficult :p Aug 30, 2016 at 22:51