Plus Puzzle

Plus Puzzle is another one of the 2010 IPP Exchange puzzles I borrowed from George Bell. It was designed and presented by Edi Nagata.

One unique feature of this puzzle that you'll notice right off the bat is that it was made out of LiveCubes (puzzle building blocks) that have been glued together. I've previously written about LiveCubes here. Some folks may not like that it is constructed this way, but it didn't really bother me. I think that Edi actually is the inventor of LiveCubes, so it is not surprising that he used them for his exchange puzzle. Since they are glued together, I was a bit concerned that they would break easily, but it ended up being pretty sturdy.

The purpose of this puzzle is to change it from the shape shown above, to the shape shown on the left. There are little nubs that fit together when it has been solved. You can sort of see the green nub in the upper left corner of the cross above.

It consists of two identical interlocked pieces, and requires a number of rotational moves to solve it (around 6-8 moves, depending how you count). It doesn't come completely apart, though the design could probably be modified somewhat to enable this. If that was done, I think it would make a great addition to Hanayama's Cast Puzzle series.

I found it moderately challenging, it took me about 10 minutes to solve. I found one of the moves to be  unintuitive in a clever way, which I think is what makes this one challenging. There is different point that I found physically difficult to navigate even when I knew the solution. You need to have the pieces lined up just right to make it happen.

It is also a bit of a challenge to get it back to the start, though of course somewhat less so if you paid attention to what you were doing in the first place. I got stuck briefly near the end, but eventually figured it out.

Overall, a nice puzzle! I like the fact that a puzzle with rotational moves like this can't be solved by a computer easily. I guess the only slight downside is the construction, but I didn't mind that much. You would certainly have to be less careful with it than if it was made out of nicely finished exotic wood! I do think it makes it a bit less compelling to play with though: I brought it to Thanksgiving at my family's house, and I think only one person attempted it (unsucessfully). Also, the 'solved' state isn't quite as satisfying as having the puzzle come apart, and it was a bit difficult to explain to a non-puzzler.

Still, it is a good puzzle that I enjoyed solving. Thanks to George for loaning it to me!