Prosecution history estoppel

Okay kiddo, let's say you made a toy car and you showed it to your friends. One of your friends said, "Hey, you should add some wheels to that car so it can move better!" You listened to your friend and added the wheels to your car.

Later, someone else saw your toy car with the wheels and decided to make their own toy car with wheels too. But you were worried that the other person might copy your whole toy car design, so you went to the toy store and got a patent. That means you get to decide who can make a toy car with wheels like yours.

But let's say someone else tried to make a toy car with wheels and say, "Well, you didn't patent the part where you added the wheels, so I'm going to make my own toy car with wheels too!" That would be wrong, because you still created the original design and added the wheels later, so adding wheels is part of your invention.

So, if someone else tries to copy your invention, they might be restricted because of something called "prosecution history estoppel." This means that anything you said or did during the process of getting your patent, like making a change or adding something, can be used to limit how your patent is used by someone else.

So while you can't stop someone from making a toy car with wheels, you can stop them from copying your exact design that you made after your friend gave you the advice to add wheels. That's what prosecution history estoppel is all about - making sure you get credit for the things you invent, even if someone tries to copy you.