I made this bag for a friend of mine who knits and has a cat that likes to "help" with her yarn...
She likes messenger bags, so I made it in that style.
I added a zipper top so Miss Kitty can't get at the yarn.
There are pockets on both sides. One side is divided into compartments for needles; the other is single for holding patterns, etc.
It's made from an upholstery remnant and lined with cotton. I used Pelon craft bond for the strap and plastic canvas to keep the bottom stiff, but the fabric was sturdy enough that the bag didn't need any other reinforcement. I made up the pattern, with separate pieces for the bottom and sides. It's hard to see from the pictures, but the narrow sides of the bag widen towards the bottom to make lots of room for balls of yarn.
Next time I'll definitely use the square-bottom bag tutorial! It's not easy to get those corners to line up properly when you're joining three pieces!