+Solution for Project Euler #189 by Shlomi Fish, L<http://www.shlomifish.org/> .

+

+Consider the following configuration of 64 triangles:

+

+We wish to colour the interior of each triangle with one of three colours: red, green or blue, so that no two neighbouring triangles have the same colour. Such a colouring shall be called valid. Here, two triangles are said to be neighbouring if they share an edge.

+Note: if they only share a vertex, then they are not neighbours.

+

+For example, here is a valid colouring of the above grid:

+

+A colouring C' which is obtained from a colouring C by rotation or reflection is considered distinct from C unless the two are identical.

+

+How many distinct valid colourings are there for the above configuration?

## project-euler/189/euler_189-2.p6