Here are three tetrahedral based ornaments that can serve as pencil holders. The two smaller ones can only hold one or two pencils but the larger one can hold several.
The ornaments make use of two of the motifs from thing:74039 - 6-Fold Plaques from Triangles. The motifs chosen can substitute for the faces of a tetrahedron. Three stl files are provided:
The program that created the stl files is pencil_holders.scad
Pencil_holder_3.stl and pencil_holder_12 can be printed directly on the build platform. Pencil_holder_6.stl has some overhang and I printed it with a raft and external support.