A more thorough explanation:

The Mirror Image Rule is a doctrine in contract law that requires any acceptance to be an unconditional agreement to the terms of the offer. This means that the acceptance must match the offer exactly, or there will be no binding contract.

For example, if someone offers to sell a car for $10,000 and the other person agrees to buy the car for $9,000, there is no binding contract because the acceptance does not match the offer.

However, in modern commercial settings, a binding contract can still be recognized even if there are minor discrepancies between the offer and acceptance. For instance, under the Uniform Commercial Code, a clearly expressed acceptance can create a binding sales contract even if the acceptance contains added or different terms when compared to the offer.

An example of this would be if someone offers to sell a car for $10,000 and the other person agrees to buy the car for $9,000 but also adds a condition that the car must be delivered within a week. This would still create a binding contract under the Uniform Commercial Code because the acceptance was clearly expressed and the added condition did not materially alter the offer.