When the truncated octahedron tiles space, the diagonals of the hexagonal faces become part of a line configuration.
Following these lines we can build the bent rhombi that we encountered in Schwarz’ P-surface, but here we will focus on the more complicated bent octagons that weave around the square faces of the truncated octahedra. These serve as Plateau contours for another minimal surface, the Neovius surface, named after the Finnish mathematician Edvard Rudolf Neovius, a student of Hermann Amandus Schwarz.
One can also fill each octagon with four copies of said bent rhombus to obtain an interesting polygonal version of the Neovius surface. Here are two such filled octagons aligned. Note that we have broken a rule: The four bent rhombi that fill the octagon are not rotated about their edges to fit together, but reflected.
Rotating about the edges by 180 degrees will create larger portions of the infinite surface.
Temporarily breaking a rule can sometimes be a good thing.
The Inner Frame 