The Uniform Commercial Code ("UCC") dispenses with the mirror image rule in § 2-207. UCC § 2-207(1) provides that a "definite and seasonable expression of acceptance...operates as" an acceptance, even though it varies the terms of the original offer. Such an expression is typically interpreted as an acceptance when it purports to accept and agrees on the following terms of the original offer: subject matter, quantity, and price. However, such an expression is not interpreted as an acceptance if it is "expressly conditional" on the original offeror's assent to the varied terms, discussed below. This language is known as the proviso. When the proviso is not used, the terms of the contract are determined by subsection 2. When the proviso is used, but there is no assent by the original offeror to the offeree's varied terms, yet the parties go ahead and perform (act like they have a contract, hence a contract implied in fact), the terms of the contract are determined by subsection 3. So, the terms of a contract under 2-207 are never determined by a combination of subsections 2 and 3.
