New shelves for my new shed

A great simple & useful project requiring 2 - count 'em - 2 different materials - screws & 2X4's. I would NOT go cheap on the 2X4's. Be careful picking over them and make sure they're as straight as possible. If some are bowed, that's OK. Just use them for the actual shelves, making sure the bow is up. I used bar clamps to hold any warped ones in place before screwing them down.