1. Lay your first color of tape, sticky side down, on your cutting mat. Put down strips of tape to make a rectangle roughly the size of an 8 ½-inch-by-11-inch sheet of paper.
2. Gently peel up your rectangle and flip your tape over so the sticky side is facing up.
3. Lay strips of your second color of duct tape directly on top of your first rectangle. Trim the edges so they are straight and square.
4. Pick which side of your duct tape fabric you would like to be the outside of your pencil case. Once you have decided the outside, take out your zipper and line it up with the pull side of the zipper facing down on a short side of your duct tape fabric.
5. Staple the top edge of the zipper to the top edge of your fabric.
6. Fold your duct tape fabric over so the bottom meets the top and staple the bottom side of the zipper.
7. Fold your stapled edges of the zipper over and secure with a half strip of your duct tape. Do this on both sides of the zipper.
8. Decide where you want your zipper to be and fold and crease your duct tape fabric, trimming any excess off the end of the zipper.
9. Staple each open end of your fabric and seal with another half-strip of duct tape.
10. Flip your fabric inside out, taking care to push all of the corners through, and you are. . .