I've been trying to come up with creative (cheap) solutions to store all my craft supplies in these open shelves. I don't have money to bay nice baskets to fill up all these shelves. I thought about making my own boxes out of cardboard, but as we were unpacking a few final boxes I came across 3 of the same boxes that fit perfectly in shelf openings. I had to trim the height a bit but other than that they fit perfectly. I first tried painting the fronts white, but the shelves are off white and it didn't work. I painted it the same colour as our walls which matched the shelves perfectly, but was too boring. So of course the next thing I went to was felt. I had some yardage left over from making a pillow and glued it on the fronts of the boxes and it looks much better and less like a cardboard box!
I think it would look best to have a fourth box (on the left) but I really like having a spot (up high) to put my camera and lenses so I can grab it quickly when I need it, so I'm undecided.