Pavel's Puzzle Blog

One of my best-selling puzzles is the Finnish Cross (formerly known as Six Tabbed Planks), designed by Matti Linkola. That might be simply because it's one of the least expensive puzzles on the website, but I prefer to think that it's because it has a compact elegance about it that makes it fit well on a executive's desk or anywhere else. I have received one or two letters about it, though, from purchasers who were disappointed at its overall size (about two inches cubed).

In its pure form, though, the puzzle has a certain fixed aspect ratio: if I made one twice as large, it would necessarily be made from plastic that was twice as thick (1/2 inch instead of 1/4 inch). It's a slow and tedious process to laser cut such thick acrylic, and some artifacts of the cutting process get magnified as well.

For example, the laser doesn't cut a channel that's at a perfect right angle to the surface; the channel is more V-shaped, wider on the 'entry' side and narrower on the 'exit' side, so the pieces end up being slightly trapezoidal in cross section rather than rectangular. Now, proper laser-cutting technique can significantly mitigate such tendencies, but as you scale up to thicker and thicker materials, the artifacts start to overwhelm the mitigations. For a 3D interlocking puzzle like the Finnish Cross, the result wouldn't be as satisfying as I'd like.

One morning, as I pondered this 'size matters' issue, I idly noted that I had managed to build up a small inventory of fluorescent blue acrylic, originally intended for use on a commission where we ended up going in a different direction. That plastic had always put me in mind of the shockingly blue ice we'd seen on Alaskan glaciers, and now that led me to picture a version of the Finnish Cross that looked like a whole bunch of icicles had been jammed together into a kind of starry, snowflakey shape. The idea really appealed to me, and I immediately sat down with my drawing software. A few hours of design later, I was ready to try cutting out the first prototype for Icicle Jam, and the result was just as striking as I'd imagined.

This jagged, icy beauty is big, about 6-1/2 inches in diameter, and really eye-catching in any setting. The internal interlocking configuration is the same as in the Finnish Cross, but I find it's a little bit tougher to visualize it in this new, more flamboyant form, making for a slightly more difficult solving experience. If you're looking for a satisfying puzzle that will really remind you of its sub-Arctic roots, Icicle Jam may be just the ticket!