What you'll need:
4 planks of wood (2' x 4')
1 saw (preferably circular but use precaution)
1 can of white paint (or other colors)
Cut two (1' x .25') slices out of each plank of wood using the circular saw. To align each cut, measure 1.33' from the edge of the wood.
Paint the wood white (or any other color really, it's your thing)
Align the interlocking joints to create a hashtag! (or bookshelf)
Tada! You have a very easy to assemble hashtag/bookshelf that is strong and durable and folds flat for moving!
If you get confused at all, you can use my blueprints as reference!