Point group S4 - 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: S4
Hermann–Mauguin notation: −4

OpenSCAD files included to make custom cells.

Further information:
ht