Octahedral Symmetry on a Sphere

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This open-source CAD software demonstrates a sphere wrapped with an octahedrally symmetric pattern. The pattern, featuring three or fourfold rotation axes perpendicular to the origin, is bent and subtracted from the sphere's surface using copies. Illustrations use Sierpinski triangles arranged for three and fourfold axes. Files include sierpinski_triangles_3.dxf and sierpinski_triangles_4.dxf, showing octahedral symmetry: four 3-folds, three 4-folds, and six 2-folds. Generated STL files are sierpinski\_x3\_small.stl, sierpinski\_x3\_large.stl, sierpinski\_x4\_small.stl, and sierpinski\_x4\_large.stl. The DXF files and open-source code to create them are also available, along with the code for creating spheres. Printing instructions note that small STL files need external support while large ones can print directly on the platform; printing time varies from 2 to 3 hours. Overlap in patterns differs between sierpinski\_x3 and sierpinski\_x4 files, but octahedral symmetry is maintained. The open-source code can easily accept other DXF files for pattern customization.