Puzzles are a problem or a game that requires the player to use logic and/or strategy to solve them. Hanayama is a manufacturer of mechanical puzzles, sometimes known as brain teasers. The puzzles are built of plastic or metal and are intended to be difficult to solve. Hanayama puzzles are ranked on a difficulty scale from one to six stars, with six being the most difficult, and frequently have a theme or a particular form. The Cast Spiral, Cast Heart, and Cast Key are three common Hanayama puzzles. Hanayama puzzles are popular among individuals who want to pass the time or practice their problem-solving abilities.