10 of the Hardest Logic Puzzles Ever Created...
Patrick Min, a freelance scientific programmer has... ...most challenging ones out there. Our pals over at conceptispuzzles .com hosted the list for Patrick where you'll find... ...and keep you busy for hours, if not days.Link via Conceptispuzzles (Thanks Gil!)
https://www.neatorama.com/2013/08/06/10-of-the-Hardest-Logic-Puzzles-Ever-Created/
