Aluminium extrusions are mans best friend. Modular and easy to assemble, and compared to the good old days they are surprisingly inexpensive. The entire housing (40x80x80cm) costs around $60 which I think is very affordable, especially when I will be able to produce a lifetime worth of toilet tissue. The entire build will cost around $500 which is substantial, but imagine the billions it will save me on butt wipes. And not to mention the hundreds of hours of fun designing and assembling and tuning it...