[defrost]

Another context here is a few centuries of past and current Anglo-sphere (UK, Canada, Australia) farming contracts and sales in general.

Stock, grain, feed, etc has been routinely traded in yards, auctions, annual shows in large units ( a years worth of lambs, feed for six months ) on the basis of a price and amount agreed upon with terse affirmatives.

A nod, a handshake, a yep, a thumbs up have all been used to seal similar scale transactions in agriculture since formal law came into being making it a solid part of common law.