The granny square is one of the most versatile crochet patterns that exists. Pretty much any project that has a surface of some sort can be made of these useful and infinitely variable building blocks. This bag is a further example that the surface made of the square does not even need to be flat. That aside, this is a very attractive bag design that will function equally well at the beach or around town. The bottom and sides are dense enough to carry your books or laptop, and the variability ensures that you can accessorize ANYTHING with this project. A link to the free pattern is at the end of the post.
Go to the pattern: