How-To: Build Nob Yoshigahara’s “Dualock” cross puzzle
I built one of these years ago from plans I saw in Slocum and Botterman’s New Book of Puzzles, and still delight in playing with it, so I was pleased as–geez, I can’t say “pleased as punch” and still respect myself in the morning, so I’ll just leave it at “really pleased”–to see this new tutorial from Instructables user Phil B about how it’s done. From the outside, the puzzle is deceptively simple: You can guess from Phil’s description that you’ve got to spin it, to win it, but there’s a devious twist. The book I saw it in had a picture of a clear plastic version that showed off how the mechanism worked, but that makes it rather too easy to figure out; the best way to appreciate Yoshigahara’s design is to build one for yourself, then give it to somebody else to puzzle over.
