**LA ORA STELO**

Designer: Jacques Ferroul

Players: 1
La Ora Stelo is a remarkably novel polyform puzzle, with pieces based on two types of isosceles triangles whose side lengths are related by the golden ratio. The golden ratio is an irrational number known as *phi* (approximately equal to 1.61803...), and has more interesting properties than you could shake a slide rule at (anyone remember those?).

When up to three of these triangles are combined edge-to-edge in all possible ways, they form a set of 32 tiles called *polyores*. Phi is very common in formulas relating to pentagons, so it is no surprise that this set rests in a pentagonal tray. It also has five small black tiles to fill the center. At least nine other sizes of pentagons can be constructed with a subset of all the tiles.

Jacques Ferroul got the idea for this remarkable set when he attended a friend's funeral and meditated on a large gold star in the church. He now has a website (http://tetrapentos.over-blog.com/article-16069070.html) on which you can find a more detailed description of this set, and links to scores of puzzles—such as arranging the pieces to form a perfect star—that will keep you fascinated and busy for a very long time.

Warning: This is not a puzzle for beginners. It demands that solvers keep very careful track of side lengths and various angles on the road to finding solutions. Experienced puzzlers will be intensely challenged but well rewarded for their efforts.
—Robin H. King