From the publisher:
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 flower. 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."
Hanayama is known worldwide for challenging puzzles and quality manufacturing. Can you take the pieces apart, then put them back together again? Hanayama cast metal brain teasers have 6 levels of difficulty, and each puzzle is Mensa-rated. Level 5 puzzles are considered difficult by most puzzlers. BePuzzled is the exclusive distributor of Hanayama Cast Puzzles in the USA.
