Here's an excerpt from Robert's description:
While not as complex as some Stickman puzzles, this box does not skimp on “aha moments”. Its devious and unique solution requires a minimum of at least 13 steps, and accessing its 4 hidden compartments can stump the most profound of sleuths.While I wasn't too thrilled that he said that it wasn't as complex as some of his other work, I did like the fact that it was less expensive than Gordian Knot Puzzle Box and potentially even more difficult! The fact that it has multiple compartments was also appealing.
I've found that I'm frequently surprised that the actual size of Robert's work is different from how I envisioned it: Gordian's Knot was smaller than I expected given all the small details, but Perpetual Hinge is quite large at almost a foot long! I think this is a good size for it though, given the mechanisms involved. It makes it quite sturdy, so I don't feel too worried letting other folks try it out.
It is crafted out of jatoba and white oak with leopardwood hinges, which gives it a fairly simple but nice appearance more reminiscent of his earlier work. As Jim notes, the mechanical-looking appearance is also a return to Robert's roots. It was produced in a limited edition of 28.
I started working on this one right away, curious to see how long it took me to find the first compartment. I checked the clock before I started and as I worked on it realized that this puzzle may be more challenging than I bargained for! I found a number of things that moved and felt like I was starting to make some progress in understanding the movements, but I still couldn't quite get it open. After about 30 minutes, I set it aside to return to later.
That evening, I again worked on it for a good 30 minutes, if not more, but didn't make any real progress. I did make one observation, but couldn't figure out how to use it. This repeated for a few days, and I decided to bring it to my parents' house for Christmas, hoping that I could make some progress. While I was there, I was suddenly able to see how to use the observation I had made earlier. It is very clever and subtle!
With this puzzle, it is quite easy to keep going around in circles thinking you are making some kind of progress. I enjoyed this since I was eventually able to figure it out, but I think a lot of folks will get frustrated and give up at this stage. Those folks should be encouraged to think outside the box, so to speak, and not keep trying the same thing. Life lessons through puzzles!
So I had accessed the first compartment and went on to find the second. I was somewhat relieved to find that it follows fairly easily after you get the first one. Of course, the rest of the puzzle couldn't be that easy: the 3rd and 4th proved quite elusive! I again set the puzzle aside to return to later.
The next day, again I found myself going in circles not making much progress. I really needed to think and not just fiddle mindlessly. I had a few ideas for how it might work, but none of them seemed to pan out. Several days later, when I was at my wit's end, I found the next step, which reveals the last two compartments!
In corresponding with Robert, he mentioned that this wasn't quite intentional, he had hoped for the fourth to require additional steps, but it didn't quite turn out that way. Still, I don't think that it is a problem at all, it was still a real beast to solve! In all, I think it took me more than a week, and probably somewhere around 5-10 hours to solve.
As far as downsides, some might not like the simpler appearance of this one or the fact that it is fairly large, but that didn't bother me. The main thing that folks may not like is the red-herring aspect that can get you going in circles like I mentioned earlier. I thought it was done fairly and with enough to get you going in the correct direction, but some might not like this feature. Indeed, Robert was initially reluctant to include this type of feature in his boxes. However, he had a change of heart when inspired by Peter Hajek's work:
My thought had always been that a puzzle was not really a puzzle unless it could be solved entirely by logical deduction, and I never was one for discovery on random chance. I was greatly intrigued by [Peter Hajek's] past IPP entry with the matchsticks and that giant red dot that really did nothing. I changed my views a bit on such puzzles at that time, and realized that the requirement of abstract thought in a solution was also a valid form for a puzzle. After all, the solution to many everyday problems often requires moving out of pre-conceived patterns of logical thought.It is interesting to hear his thoughts on it, and I totally agree. Of course, it is the task of the puzzle designer to make sure that the correct path of abstract thought is possible at some level, and I think Robert did a good job with this.
Overall, I think this is an excellent puzzle that I'm very glad to have purchased. I don't think I like it quite as much as Gordian Knot, but that's currently my all-time favorite puzzle so it is hard to compete! I can't wait to see what Robert comes up with next!
Check out Jeff Chiou's blog entry about this puzzle as well to read about his experience.