This Nuts And Bolt Puzzle Is Supposedly Impossible...
The trick to disassembling the puzzle relies on two hidden bits of unusual design. There's one on the bolt and one on the nuts. But if you don't want to find out what they are before you try it yourself, fair warning: spoilers ahead. So here it is...Mr. Puzzle gives a rundown of what this puzzle appears to be at first glance and then if you're willing to have the mystery spoiled, you can see what's really on the inside:
Usually, there's nothing complicated about a regular nut and bolt pairing. However, this isn't your average nut and bolt. The"Nut Case" puzzle by Hanayama is a puzzle in the form of an apparently unsolvable problem: two freely twistable nuts trapped on a bolt with a head on either side. And of course, as always with puzzles, there's more to it than meets the eye. But there's also a bonus for all you problem solvers out there...if you know what you're doing you can not only free both of the nuts, but there's also room in the device to hide something small.
So for those of you who didn't watch the entire video, the double-headed bolt is actually hollow and made of two pieces. Each one has a pair of rectangular slices taken out of the cylindrical body. The voids of one piece match up with the protrusions of the other, and that lets the two fit together as a single cylinder.
On the other hand, the nuts have gaps in their internal threading which mean that when aligned correctly, they can slide freely when they're only on one-half of the bolt instead of on both at once. But you'll have to check out the whole video above to see it in action to really understand.
There's not much room inside, so don't be expecting to hide anything larger than a few screws or a smaller nut, but on the upside, whatever's inside will be secure. Until the next problem solver comes along at least.