I made a flask out of one of my sculptures. This flask is made from a shrunken head that was sculptured by me. Now this guy says he has a patent pending and he is going to sue me. If I have never seen his product how can this be? Is there a rule on how many similarities a product must have to infringe on his patent? Or how many differences I must have if his item is patented?
First, once someone says "sue", I would contact a lawyer to get actual advice. I am knowledgeable about patent law but am not an attorney.
A pending patent wouldn't give anyone the right to sue. They could put you on notice that their application is on file and that if and when it issues as a patent they think they will have rights they could use against your activities.
If they end up with a patent, the fact that you independently developed your product is not a defense. Copyright involves copying, patent infringement can be "innocent", and still be infringement.