I've taken some scrap clay, mushed into working condition with my hands, ran it through the thickest setting on my pasta machine a few times, and trimmed it to measure six inches tall and 3.5 inches wide. It's gonna be the backside of my bookshelf.
Next, I'll make another sheet of this scrap, just a bit thinner, and add it straight on top of this one. Then make the sides and the shelves, etc., then make some "wood" and cover it all so it looks like the real thing.
I'm not sure if I ought to build it then bake it, or if it'd be best to bake the parts separately, then superglue then on. The biggest plus of working with raw clay is that you can mold things as you go. For instance, if I make a measurement mistake and the clay's still uncured, no one will ever know, because I can just moosh and smooth everything into place.
The biggest con of working with raw clay here is that it droops and bends in the oven, requiring me to prop it all up, perfectly, before it goes in to bake.
The other option would be to bake the pieces separately. So I would take the two-layered bookshelf back, lay it flat on a piece of waxed paper on a tile, lay another piece of waxed paper on top of the clay, lay a tile facewise down on top of all that, and bake it. Clay likes to bubble while it bakes, which is why the tiles are needed-to squash any bubbles that try to crop up. End result, I'll have straight, clean pieces with straight, clean edges, but no room for errors. No mooshing and squooshing and blending in. There IS haevy-duty sanding, but I am really bad with it.
Truthfully, I will probably try it both ways to start with, and another six ways I haven't even thought of yet before I'm through.