Every year, serious puzzle collectors from around the world gather to buy, sell, swap, and discuss puzzles at the International Puzzle Party (IPP). A major part of the IPP is the puzzle exchange, where participants bring copies of a new puzzle design to exchange with up to 100 other participants. At the end of the exchange, each participant then has a new puzzle from each of the other exchangers. You would think that this would be enough puzzles to keep them busy till next year, but for these collectors, it is not even close.
After the puzzle exchange, leftover puzzles are frequently sold at the following puzzle party, which is a large puzzle market featuring a wide variety of the worlds finest puzzle masterpieces from the best craftsmen in the world. I use the term craftsmen loosely since a few of these renowned craftsmen are women.
One of my primary goals every year is to acquire the puzzle exchanged by Frans de Vreugd. The designs by Frans hit my sweet spot in terms of puzzle complexity and enjoyment. When Frans does not provide a puzzle of his own design, he makes sure to provide one of the same caliber.
Frans’ exchange puzzle for last year was Identity I A designed by Andrey Ustjuzhanin. It consists of four identical pieces packed into a U-shaped frame. Although many exchange puzzles may be of a slightly lower quality than a craftsman would make to sell, the Identity I A puzzle is of top notch quality. The frame is made from wenge, one of my favorite types of wood for puzzles. The pieces are equally nice, but I’m embarrassed to admit that I don’t know the exact type of wood used. The puzzle is nicely finished and the frame even uses dowels to reinforce the joints. The color of the pieces and dowels contrast nicely with the dark wenge frame.
The puzzle came assembled and I quickly removed the pieces from the frame and let it sit for a while. I like to provide enough time to forget any of the disassembly process to make the assembly more challenging. After all, it’s only five pieces that have to go into the frame and they are all identical. How hard can it be?
I sat down with the puzzle expecting a short session to get those few identical pieces in the frame and was chagrined that I didn’t allocate enough time to get it assembled. It took another longer session to figure out how all the pieces go back in the frame.
Usually when solving this type of puzzle, I like to determine how the pieces would be combined outside the frame and then determine the order that they need to be inserted into the frame. I found this approach more difficult than usual with this particular puzzle due to the large number of voids in the final assembly and abandoned it in favor of simply working with the pieces within the frame. The frame can hold 40 cubes and the pieces only use 30 or 75% of the space within the cube.
It turns out that there is only one way that the pieces can reside within the cube but the pieces can be added in different orders. The ordering that requires the least number of moves provides a difficulty of 126.96.36.199.2, i.e., 4 moves to take out the first piece, 3 to take out the second, etc.
Packing puzzles where all the pieces are the same are not new but this one is particularly elegant given that it only has 5 pieces and is a non-trivial packing/interlocking puzzle. The fact that it is so nicely made makes it even more special. I’m looking forward to this year’s exchange puzzle.