In the game Hard Jigsaw Puzzles you have to strain a little and have a good brain. And there is something to think about. These puzzles are not pictures that we are used to, but geometric shapes. For example, at the first level, it is proposed to assemble a square from many small components. If, when folding a traditional picture, everything is clear – pick up pieces of the image, then here the task is an order of magnitude more difficult. It will take a high level of spatial thinking to combine all the fragments and get a given figure. So it won't be boring.