About this 3D model
Here are four pencil holders, two based on the snub cube and two on the snub dodecahedron. A fifth has been added - a snub cube composed of spheres and hypocycloids - see image. Of the Archimedean solids only the snub cube and the snub dodecahedron occur in mirror image pairs. OpenSCAD has a "mirror" command which makes the alternate forms easy to generate. Four stl files are provided: snub_cube_l.stl and snub.cube_r.stl snub_dodecahedron_l.stl and snub_dodecahedron_r.stl together with the openSCAD code that generated them.