This puzzle contains 10 identical pieces. The puzzle is to put them together into a ball. This is not too difficult except for the last piece. The interesting part is then getting it apart. It will only come apart when all 10 pieces move at the same time. This is almost impossible to arrange, except using centrifugal force, i.e. SPIN IT! If done with sufficent speed,
it blasts apart into a pile of pieces (UTube video).
This puzzle was designed by Stephen Chin (of Sydney, Australia). He is a woodworking expert and a wizard with the lathe. The first photo shows one of his creations. Making this puzzle out of wood is very time consuming. After gluing each of the 10 pieces together from 4 tetrahedrons, he fits it together into an icosahedron. Then he puts it on his lathe and turns it into a sphere. Since this puzzle explodes when you spin it, you can imagine this is hazardous. He actually has to glue all the pieces together (temporarily) for this step. Then he takes it back apart and removes all the glue. These puzzles are works of art and a lot of fun, he sells them for $250-$300, and that is a bargain.
Stephen asked me if it was possible to print this puzzle on Shapeways. After 3 months and 6 prototypes, it is finally a reality. This puzzle is difficult to make, because it all depends on some very carefully chosen angles. If everything is not perfect, the puzzle won't go together, or it won't come apart when spun. The puzzle exploding depends on the friction between the pieces, and this is quite high for WSF. The wood puzzles tend to work very well because the pieces are slick and slide against each other easily. However, the wood version is susceptible to changes in humidity. The pieces are also not all the same, and must be reassembled in a particular order to make the perfect sphere.
At last, I am happy with the design and have put the puzzle up for sale in my shop. It is available in a
4cm diameter size, and
5cm diameter (my favorite). Eventually I will also add a 6cm version.
The friction between the pieces tends to be a bit too large out of the printer. Therefore, this puzzle requires a tiny bit of sanding on all interior faces. I recommend 320 grit sandpaper, and the goal is not so much to remove material as it is to make the pieces smoother. Because of this I offer it ONLY in white, strong and flexible. All other materials are too brittle for this puzzle. The one in the photos made out of alumide is actually broken.
The wood version of the puzzle, by Stephen Chin.
The ten puzzle pieces.
The assembled puzzle (5cm size)
Lots of exploding ball puzzles! Many of these are prototypes and don't work or are broken.