How a set of three pieces can create an intrigue when this intrigue is wrapped in a clever puzzle? The time proves such puzzles existed decades or even centuries ago and the practice shows they are invented nowadays on quite a regular frequency.
When it comes to mechanical puzzles it always comes to pieces. Often, the more the pieces, the harder the puzzle can be. In some puzzles the number of pieces can reach hundreds or even thousands. Jigsaw puzzles, for example.