Bowling Alley in a Briefcase

I went down to Eureka to pick up the DanLock that I had loaned to David one day. He had recently returned from the 2009 International Puzzle Party, and had all sorts of new puzzles to show me. I saw a few of Allan Boardman's tiny burrs, an original Stewart Coffin, Ring Box by Gary Foshee, and a ton of other stuff.

David was kind enough to offer to loan me a copy of Norman Sandfield's Bowling Alley in a Briefcase by Kathleen Malcolmson. I had seen this type of briefcase design before, there are several types, and was excited to have the opportunity to give one a try. I had no idea what to expect, other than that it would be quite challenging.

I worked on this puzzle for quite a long time: I am not particularly experienced with hidden mechanism puzzles, so I think that contributed to its difficulty. I shook in around all sorts of ways and had a hypothesis about what was going on inside the briefcase from the noises I heard, but I had no luck getting it to open!
This continued night after night, working on it for an hour or so each night for about two weeks before I finally broke down and asked David for a hint.

I told him all of the things that I had tried and my hypothesis about the workings, and he gave me a hint that I thought gave away the solution. When I tried it, however, it still failed to open! I tried that night for about an hour, and even with the hint, it still wouldn't open, which was fairly frustrating.

The next morning, right after waking up I went straight back to that briefcase. Finally, something clicked (mentally), and I figured it out. Now that I know how it works, it seems so simple, but it is a real challenge to figure out what is going on inside when you can't see. This is a very cool puzzle, but was quite a challenge: not for the faint of heart! It is very nicely made and well designed, a thoroughly enjoyable puzzle.

Tomorrow, I will write about a presentation on mechanical puzzles hosted by Eureka, where I met a bunch of Boston-area mechanical puzzle collectors.