What are those spinny things called that they used to have in diners where the waitress' put their orders on the thing and the chefs can spin it and take the orders off?

Those spinny things are called "order wheels" or "kitchen wheels." They are used in diners and restaurants to facilitate communication between waitstaff and kitchen staff, allowing waitresses to place orders on the rotating platform for chefs to easily access. This system helps streamline service and improve efficiency in busy dining environments.