Models of a Skew Polyhedon

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This regular skew polyhedron was first revealed by Petrie during a lively discussion with Coxeter in 1926. Check out Coxeter's paper on "Regular Skew Polyhedra in Three and Four Dimensions and their Topological Analogues" published in the Proc. London Math. Soc., ser 2, 43, 33-62, 1937, and also explore https://en.wikipedia.org/wiki/Regular_skew_apeirohedron. It's composed of a regular infinite array of squares, six of which surround each vertex. You can view models similar to the one shown in Coxeter's paper to get a better understanding of this concept. The OpenSCAD code is included below. A simpler and more parametric version of the openSCAD code, "unit_cell_multiple.scad", was added on May 2, 2018. It was observed that this arrangement of squares falls under space group 229 with six squares in the repeating unit - check out the openSCAD code for details. The file "unit_cell_contents.stl" shows the unit cell contents and clearly displays six squares meeting at a vertex.