I really like the simple shapes and the bare plywood interior. I might add a thin white wash to the walls. Something to keep them fresh through time. Add a tiny kitchen and bathroom to this design and you might be able to live in it full time. Bravo!
This great example of cast iron architecture I found on Wikipedia is stellar. Placed here to remind me. So often I daydream about minimalist styles. But then I see this beautiful work and know that more detail is super important to me.