Impossible Ring Puzzle!
This is a not too difficult, but quite clever puzzle. The task you need to assemble those two pieces here in the shape of a ring, but this is the delivery condition and, as you can see, it’s quite impossible to do so. You can screw these apart, which reveals both of them have a thread down here, but every time you symbol them here you get back into this condition and are not able to get it in this ring-like shape. The solution is quite clever because you need to think a bit out of the box, and this is how it looks like. Of course, you need to use this thread to screw them together.
There is no other way, but the way how you start need to be different. You need to join the two pieces like so and then screw them in the other direction, which enables you to get the ring assembled and solve the puzzle.