Point group D2d - Dual extruder

"In crystallography, a crystallographic point group is a set of symmetry operations, like rotations or reflections, that leave a central point fixed while moving other directions and faces of the crystal to the positions of features of the same kind."

https://en.wikipedia.org/wiki/Crystallographic_point_group

This is a dual-extrusion model.
Tetragonal cell.
Schoenflies notation: D2d (Vd)
Hermann–Mauguin notation: −42m
Orbifold: 2*2

OpenSCAD files included to make custom cells.

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