Mette from Monsters Circus shows how you can transform a basic canvas tote bag into a drawstring backpack, with no sewing required. It’s an easy transformation, adding a casing to the top, and ring tabs at the bottom. In place of sewing, she uses E6000 to hold it together. You could very easily make this a sewing project and stitch those pieces of fabric down instead.
Click for the tutorial: DIY from Tote Bag to String Bag, by Monsters Circus
[photo from Monsters Circus]