Not that I have an empty closet, but i do like this."Closet Office" - Turn your un-used closet/reading nook into an office space. Maximize the little space with lots of shelving and storage *LIKE CORNER DESK/nook & shelving for office corner
I would do the boxes next to each other (or shelves for art supplies & books), add a cushion on the boxed (shelf area) with textured pillows. Then add a leg to support the desk on the end with two chairs.