Fractal tray puzzles are high quality wooden puzzles based upon space filling fractal curves. The pattern is a single line that crosses all of the two dimensional space without ever repeating. The puzzles follow these simple rules to break the line into multiple pieces that are almost identical but are actually unique. The pieces are so similar in style that once they are placed into the puzzle it is hard to see where the pieces are. The puzzles can be tricky to solve even if you have the solution on hand.
There are 4 space filling curves that lend themselves well to this type of puzzle.