An icosahedron has 20 faces which are equilateral triangles.
Tom wants to create a very hard mechanical puzzle. With his brand new 3D printer in mind he designs 20 puzzle pieces with identical shapes which in principle nicely fit together to build the icosahedron:
The face ofthat is visible after assembling the assembled icosahedron is on the back here.
To hold the parts together he uses magnets which he glues into the prepared 5 holes in athat he had prepared quite devilish waydevilishly.
There are exactly 10 ways to orientateorient the magnets such that two magnetmagnets are orientated to the outsideoriented with the north pole, thesepoles facing outwards. These 10 parts he wants to print in yellow. Here is one example:
And of course there are also exactly 10 ways to orientateorient the magnets with two south poles to the outsidefacing outwards. These 10 parts he wants to print in blue. Example:
Hey, we got a complete set of exactly 20 different pieces! There are $19!*3^{19}$$19!*3^{19}> 10^{26}$ ways to assemble the icosahedron if we ignore the magnets.
- So should notIs at least one ofway for the more than $10^{26}$ combinations hold nicely togethermagnets to match everywhere (north poles matchto south poles everywhere)?
- And to top it all, isAre there eventually an especially nice looking solutions with 5 fold-fold symmetry? TheObviously, only the colors of the pieces obviously are only interesting for this part.