The puzzle, Bubble Universe, has started selling today. This is a puzzle to pack all the pieces into a tray. The tray has two concave sides, one circular and one square.
I have played with both sides, and I would say either side was difficult for me. The pieces seemed to fit into the tray, but they did not. In the end, I wondered if there was an answer. Believe it or not, there is. I do not know how many solutions there are. Maybe, you will find them.
People tend to think that three-dimensional puzzles are more complex than two-dimensional puzzles. Generally speaking, it may be true, but this puzzle is not easy. Do not underestimate this puzzle.