This one is kind of a joke and an experiment in just how cheap you can build a guitar. The body is dry-erase board over plywood - no finish - with Tolex side binding. Dry-erase board is Masonite covered with Melamine. The neck is 100% Radiata pine, even the fretboard. The "inlays" are glitter and CA glue. The pickguard is the other side of the dry-erase board - 'chalkboard'. The pickup mount is a 57 cent switch plate.
This is my favorite truss rod design. It is not my most advanced, but it is the simplest to build. Although it is a single-acting rod, a little forethought in routing the channel makes it reversible, effectively double-acting. That requires some disassembly of the guitar, but you only need to change the direction of the rod once or twice in the life of an instrument, until it settles in to a mature shape.