Warning: This collar is designed to give an animal more freedom than an E-collar and therefore cannot be used in every situation that an E-collar is used. In particular, it may not prevent an animal from licking/biting its front paws or the end of its tail. However, with cats (and some short faced dogs) it will prevent the animal from using its front paws to scratch its face. In any case, you should always watch your pet for a while to make sure this collar works as intended.
Step 1: Materials
For large dogs you may want to fill the inside of the foam with cloth or smaller diameter foam so the dog can't simply crush the collar.
2. Electric or other plastic tape. The kind of tape you use is important as the collar is inevitably going to have contact with whatever your pet eats and drinks. I tried cloth athletic tape first and within a couple of days I had to negotiate terms with the colonies of bacteria that had seized control of the collar.
3. Shoelace, or other thick piece of string.