my second post, my mechanical puzzle obsession actually started with an order from ThinkGeek.com: I ordered a Legend of Zelda t-shirt and decided to buy a few Hanayamas, which kicked off this whole wild ride into the land of the mechanical puzzle people. Anyways, I follow ThinkGeek's RSS feed for new items and items that are on sale, and they were having a sale on V-Cube 7's for $45, which was a good price for them as far as I could tell.
So I decided this would be a good time to give one a try and test whether or not I could generalize my knowledge about 3x3x3 to solve a 7x7x7. While I was there, I noticed that ThinkGeek had a few other twisty puzzles that were pretty reasonably priced too, so I ended up buying Megaminx, Rubik's Mirror Blocks Cube, and a knockoff Square-1 named Irregular IQ Cube. I thought that I might as well confront my fear of twisty puzzles head on! I guess I am kind of a sucker for a sale, and it worked just like retailers hope: the sale brought me in and I ended up buying more than I expected. And, to top it off, the V-Cube 7 is still on 'sale' months later!
This puzzle was quite baffling to me. I had trouble even getting it back into a square shape, much less getting the colors back on the right faces. I was able to get it back to a square and partly solved, but then I got stuck. I worked on it for a few more days and haven't really spent much time on it since. I think if I had a better version I would be more likely to play with it, but fighting this one as it jams isn't a lot of fun. I'll probably buy an actual Square-1 in a while and see if I can figure it out.
I picked a random face to be the bottom and started to work my way toward the top. It was quite a challenge, especially with the large number of colors and I frequently screwed up and messed something up that I had previously solved. Eventually I figured it out though, I think it probably took me about two hours. The hardest part is getting the final pieces in place, because you need to do it without messing everything else up. I tried a bunch of moves and eventually found one that was similar to a 3x3x3 move that I used for a similar purpose, and it ended up working. Nice!
Eventually I decided to go for it and scrambled it up. If it looks daunting when solved, it was even more so when scrambled. I decided that my strategy was going to be solving the faces first, then the edges, then the corners. I worked my way from the center of each face outward in concentric squares, getting the 3x3 solved on each face before proceeding to get the 5x5 square solved and so forth. This took me a very long time. I didn't time myself, but it was probably 3-4 hours. I developed a little set of moves that would cycle three pieces between adjacent faces that worked pretty well, but it took a very long time to position each piece individually.
Next, I moved on to the edges, which weren't too hard...at first. Once I got to the end, I realized that my move was a 3-cyle and I need a 2-cycle to finish! (A move that would switch two edge pieces). Try as I might, I couldn't find a move that would break the 2-cycle. I kept ending up with other configurations that just reduced to a 2-cycle. Eventually by trying a move similar to a 3x3x3 move that is a two cycle, I managed to get the edges in a state where they could be solved by my 3-cycle move. I think this whole process took me about a week of working on it for an hour or two per day. Needless to say, I was quite satisfied when I finally figured it out.
Now came the easy part! With the edges solved and the faces solved, I could treat it just like a normal 3x3x3 cube. Needless to say, I was very careful, but after a few minutes I had it back to the solved state! I was quite pleased with myself!
That said, I haven't tried to replicate this feat since I have solved it. Writing this makes me remember how repetitive it was! I think it would be just as satisfying and interesting to do a 5x5x5 and it would take quite a bit less time. If you know how to do a 5x5x5, you pretty much can do a 7x7x7, so if I had it to do over again I might just do that instead. Still, it is kind of cool to say I have solved the 7x7x7!
You might note that I didn't mention the 6x6x6, that's because my understanding is that even cubes are somewhat different from odd cubes because there is a parity problem that can occur. This seemed like an added annoyance that I would rather not deal with, which is why I haven't bothered with even cubes other than the Triple 2x2x2 I blogged about a few days ago.
Whew! I didn't think I was going to be able to get this entry done in a single night, but I was on a roll. Hope you enjoy it! Tomorrow I'll write about some more Karakuri boxes!
2 days ago