A buyer mailed a signed order to a seller that read: "Please ship us 10,000 baseballs at your current price." The seller received the order on January 7 and, that same day, mailed to the buyer a properly stamped, addressed, and signed letter stating that the order was accepted at the seller's current price of $1 per baseball. On January 8, before receipt of the seller's letter, the buyer telephoned the seller and said, "I hereby revoke my order." The seller protested to no avail. The buyer received the seller's letter on January 9. Because of the buyer's January 8 telephone message, the seller never shipped the goods.

Question: Under the relevant and prevailing rules, is there a contract between the buyer and seller as of January 10?