Its a triangle, twisted, extruded and supported inside and out. There is actually a lot going on with this design but it has been incremental, so enjoy! Please scale down to fit your printer dimensions but I found 25% scale of original is VERY strong. Added a second copy of the scad file. (less comment) Final Version is updated with vectors and modules. MUCH cleaner and easier to read. Also, much easier to modify and create with.wanting to learn more about linear extrusion, I downloaded a twisted box stl file. However, I wanted only the wire frame. So I applied the linear extrusion code to my extruded triangle openscad file. This created a nicer to look at extrusion but easily breakable design. (twist oppose the extrusion) So I added 'inner' pillars to help support the midpoints of the triangle. (offsetting offsets with trig is interesting) Lastly, I reversed the 'polarity' (?) of the inner pillars to see what happens. Wow. From being flimsy with an achilles heel to being structural sound, what a difference a negative sign can make.