As long as you don't make a mold from an existing lure or infringe on a trademark shape, it is legal to design your own shape or use the shapes available in pre-packaged molds available for sale. Instead of getting a patent, many lure companies actually get a "Trademark" for the lure that covers the shape of the lure (much cheaper!). It is illegal to copy someone's trademark, so that is how the shape of the lure can get protected. (Disclaimer: We're not attorneys - always consult an attorney for legal advice) :-)