 However, if B ships the red coathangers with a note that they sent these because they had run out of blue coathangers, this is not an acceptance, but rather an accommodation, which is a form of counter-offer.An interesting implication of the operation of the posting rule is that an acceptance is complete once the letter of acceptance is posted; it makes no difference whether the offeror actually receives the letter.This was demonstrated in "Byrne v Van Tienhoven" (1880) 5 CPD 344.