I am a big fan of 3D spatial puzzles; you know, those things with the bars, and ropes and balls and holes, where you have to twist the parts around and loop them and pull them and so on to free one or more pieces.  What can I say, they're fun.

So, my daughter Megan brought one home recently that was the best one I've ever encountered.  First, it was really hard, and second, it is deceptively simple, and third, it is composed entirely of three solid parts.  Here it is in its original state, with the three parts intertwined:

The puzzle, original state.  (click for closeup)

At first it doesn't seem there is any way to do anything, the pieces have plenty of "wiggle" room, but you can't seem to change their spatial orientation relative to each other.  I literally spent three days off and on playing with the puzzle before I could even make the first move.  After that I realized it wasn't a joke (!), and I realized it was a great puzzle.  Everything you try almost works, but then some little geometric feature of a piece prevents it from working.  Finally after about a week I was able to free one piece!  Yay.  But I couldn't free the other piece, and I even starting thinking perhaps that's all there was to the puzzle; that the goal was to free one piece, and leave the two others linked.  And then yesterday as I was looking at it again, I thought to myself: "the people who made this puzzle did a great job.  They would not have designed it such that two pieces were left linked."  So finally, after about an hour of futzing (!), I was able to separate the last two pieces.  Yay.  And whew.  Here it is with the piece separated:

The puzzle, solved.  (click for closeup)

Awesome.  What's really amazing to me is how was this puzzle designed?  Each piece has this weird shape, perfectly designed to fit and be manipulated in only one way, and to create problems for every other way.  Someone must have spent a lot of time laboriously crafting this puzzle.  And to what end?  So it could be sold for $25 in a novelty store?  Or so I could enjoy solving it, and blog about it?

Bonus question: if you wanted to Google for this, how would you do it?