PLA-Tonix is a series of 3D printed Platonic solids that use hinges to open up and show cross sectional geometry. The icosahedron comes with three cross sections, including: a nonagon, decagon, and a pentagon. The model was printed in PLA. The solid is presupported with several pegs between cross sections, and a pair of small arch supports at the start of the pentagonal cross section. Just snip these with a pair of standard snips and gently break the hinge open. I've attached pre-sliced G-code for the Ender 3 and Prusa Mini+. Both are sliced for 0.4mm nozzles, draft quality, with brims and for PLA.