respect to the $40 copy. Sushi restaurants serve a variety of dishes with high variable costs. The market price for different kinds of fish can change dramatically in a short period. Some restaurants have expensively printed color menus with set prices. Others let you choose items from a conveyor belt or floating boats; the color or style of the different plates corresponds to a price on a card. This system removes friction from the pricing process: when costs change, it is easy to adjust the price for