Tetra'Aide
thingiverse
Each piece is assembled by inserting a 1.75 mm filament into each hole. Explanation of Tetra'Aide's usefulness: http://bdemauge.free.fr/tetraaide.pdf I've added the part of the tetrahedron without inscription (Tetracorrected.stl) to let your imagination run free :-)
Download Model from thingiverse
With this file you will be able to print Tetra'Aide with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Tetra'Aide.