A polyhedral shape interlocking puzzle designed and made by Junichi Yananose (aka Juno) in 2017. The shape of the puzzle is based on a compound of five tetrahedra. You can see in the image below that five color tetrahedra intersect each other and form a star shaped polyhedron. You will also find the same construction formed by the inner elements of the dodecahedron model of Juno's Spinner.
A few people designed puzzles shaped with a compound of tetrahedra but as Juno recognises, on those puzzles, each tetrahedra just touches the others on their edges or faces but actually doesn't intersect. Some are more like geometrical art rather than a puzzle. His challenge of the puzzle was to make all five tetrahedra intersect each other and designed it as a real puzzle.
He also considered it was an important task for himself to make the shape of all 30 pieces different. It was easier if most of the pieces were identical and there were only a few key pieces to take the assembled puzzle apart but he thought it was boring. His efforts came into bloom and it made the puzzle very challenging. The difficulty of the puzzle is extreme, and he would say that someone who tries to assemble the puzzle without checking the solution is brave or a genius. Although the puzzle can be assembled by two hands, it is very helpful to use rubber bands at the early stage of the assembling. Juno usually uses three rubber bands for assembling and those positions can be made sure on the solution sheets.
It's a big heavy puzzle. The diameter of the puzzle is almost the same as Reza 12-20 but the mass volume is slightly smaller. There are a total of 120 checkouts on the pieces. 7.2 lineal meters of timber, without considering the waste, was used for each puzzle. The ends of the pieces were trimmed off diagonally leaving a small flat surface because if the assembled puzzle stands on a flat surface supported by the sharp, pointy five edges of the pieces, it might be easily damaged. He lost lots of pieces during the production and only 15 puzzles survived, so we have only 14 to sell. Juno has no plan to make another batch at this moment.
Mirii is an Aboriginal word meaning star in English. We thought that it is a good idea to give an Aboriginal name since we have been living in Australia. We think that the sound and name match the shape of the puzzle. CFT is an abbreviation of compound of five tetrahedra, used to make the name of the puzzle shorter.
The puzzle is sold assembled. The PDF version solution will be provided upon request.
Diameter of the circumscribed sphere: 274 mm
Length of the pieces: 240 mm
Number of pieces: 30
Material: Koto, Blackbean, Queensland Maple (citrus family tree), Jarrah and PNG Rosewood
Designer: Junichi Yananose (Juno)
Origin: Made in Australia