So: a town hall announces a sale. Locals sign up for what they want to buy. The town hall then tells Kamenides the quantity required and he and his students cal

So: a town hall announces a sale. Locals sign up for what they want to buy. The town hall then tells Kamenides the quantity required and he and his students call local farmers to see who can supply it. They show up with the requisite amount of produce at the appointed place and time, meet their consumers, and the deal is done. This is just screaming out for a mobile/web app.