How much difference does there need to be between an already patented product and what I want to sell?
This is a technical question really, you read a patent by reading the claims, which are the numbered paragraphs at the end of every patent. Nobody knows what they are, but that’s what you get when you get a patent, they’re analogous to the metes and bounds description. The pieces are real property. Each piece of dirt A is separate from the other piece of dirt B by the deed. You know, when your neighbor’s dog is in your yard. So you look at the claim and if it has five elements, for example, that define the invention that you want to get close to. If you have all five of those things you are infringing the patent. If you have four of them, but not all five, you’re not infringing. So that’s how close you can get. If you can make the thing with four and not the required five, you’re okay.