For my project, I have chosen to build a toilet. My final toilet design is and outhouse on stilts. The fours walls of the outhouse are closed, with a tin/scrap metal roof. The structure is built mostly from wood. If you are looking at the door of the outhouse,three steps lead up to the door. On the two sides of the outhouse, wood planks go all the way to the ground, creating a wall. This is for stability and hiding the waste barrel. My final design:
Looks good. It is neat and not falling apart.
Is not too expensive if you use scrap metal and wood or a mix of new and old materials.
It is efficient. You can easily remove the waste barrel and the door will not sag of it's hinges.
It is also realistic. It is possible to create.
I chose the toilet too create, because it is not too expensive and it still looks decent. It is efficient, you can remove the waste barrel easily and opening the door is no problem. The inside is simple, but it works. A whole in the floor, but not two planks just ripped out. The whole structure is stable too.