After Global Day of Coderetreat 2015 a few of us went to Ruby Burgers, an informal meetup organized by local Ruby Zagreb group. The most interesting presentation was a puzzle by Brunt Šutić. I have tried to debug a small piece of Ruby code on his machine and failed. It was a fun puzzle, and I was not even close. I will not talk more about it, since I do not know if he plans to use it again. :)