This will be good to have pinned later for that time of "there's too many shoes but I can't afford decent shelving yet" --- Shoe explosion? Round up some old tension rods, set them up in your closet, and voilà, instant customized shoe rack!
Something else I wanted to do long ago, and now we're in a different house with much wider closet doors. I guess they could still put it in a bedroom doorway. This could not be easier, just two tension rods and curtains!