We've used a similar corner shelving unit to create space in a small 7 by 9 ft room. It's a great, easy shelving solution for small spaces (although installing it was a bit tricky as the walls weren't plumb.
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Built in tree book shelf - Inspiration Only but this is gorgeous. I so want this in my next home. There is also another tree on my project board I want to put in the same room as this. This would be great for a kid& room.