Step 2: Harvest
Step 3: Build
Step 4: Use and Variations
Different size bottles, and different cutting of the rectangle can give you caes for various uses. Watch for my upcoming battery case instructable!
Some credit must go to: Plastic Soda Bottle Lid Capsule: http://www.instructables.com/id/Plastic-Soda-Bottle-Lid-Capsule/ and where one of the comments may have mentioned this techniques but there are too many comments for me to read.