Hanayama Helix Puzzle
The grooves engraved in the two rotating boards are called "logarithmic spirals." These two grooves always cross at right angles, and a square hole is formed at their intersection. The goal of this puzzle is to remove the helix ring that goes through that hole. The inspiration of this puzzle is the morning glory. The puzzle was designed to look like a bud that comes into bloom with twining tendrils. The original concept dates back to 1990, but it has been enhanced with the addition of several tricky features. The theme of this puzzle is "Flower."