Math Teachers' Pencil Holder / Stand, Hyperboloid, Ruled Surface

thingiverse

Math Teachers' Pencil/Straw Holder /Stand, Hyperboloid, Ruled Surface This classic display for a ruled surface (hyperboloid) is perfect for classroom use with pencils or straws, just like David Hilbert's famous book on imagination and geometry suggests. It comes in four versions: two hole diameters (8.5mm and 9.5mm), single or dual rings, all with the same great results. The outer diameter measures either 127mm or 129mm, holding up to 48 pencils or straws at a time. Once some pencils are inserted, try lifting the ring up slowly and letting them drop slightly for a perfectly symmetrical structure.