How was this thing built?
Simple and basic construction using 1x3 studs and 1/4, 1/2 & 3/4 inch plywood. Everything is "Screwed and Glued" a method I thought was my own but come to find that this is a common construction Practice.. When you secure a piece of plywood or 1x3 that has been covered in "liquid Nails" Construction adhesive with drywall screws you create a bond much stronger then any bolt method possible. The 2 pieces of wood will not come apart without busting up the wood itself. It a freaking brick wall..... If you doubt this try building a square box using this method then try a sledge hammer to get is apart again. Good luck with that :)

From the inside

From the outside
Early Rear Profile Drawing