Buyer 1 makes an offer.
Seller makes counter-offer with an acceptance deadline.
Buyer 1 counters the Seller's offer. Buyer 1 learns that Seller has received a competing offer from a Buyer 2 and to avoid losing the property to Buyer 2 . . . Buyer 1 purports to accept the Seller's counter-offer from step 3 within its acceptance deadline. The Buyer's counter in step 4 is a rejection of the Seller's offer in step 3 and terminates Buyer 1's power to accept the step 3 offer. There do not seem to be any Colorado appellate cases directly addressing this issue.