This simple bag is not as simple as it looks on first sight. The clever way the strap is connected makes sure that the bag closes automatically when picked up.
Backpack Bag DIY Tutorial
I have always wanted to make a 'just the right size' backpack bag because as a city dweller it's good to have a nifty bag that will securely hold the essentials, but will leave your arms free so you can more easily fend off the maddening crowds carry your bags of shopping.