My daughter is only 9 years old, but she is really good at making stuff with duct tape. This is a simple backpack that she made herself. The only thing she used was duct tape and Velcro! Here are the steps.
Step One: Make two sheets with twenty strips of duct tape each.
Step Two: Take a textbook to see how wide you need to make the bottom. Tape the bottom onto the sheets.
Step Three: Tape the sides of the two sheets together.
Step Four: Use sixteen strips of duct tape to make the flap and then tape it to the top of the bag.
Step Five: Add a strap.
Step Six: Feel free to add a design or pockets to your backpack!