Familiar categories; different context
In California, gas stations usually show three prices: regular, mid-grade, and premium. Sometimes diesel is shown. Even if there is small text to explain what those prices refer to, we mostly go off of familiarity, knowing what each box in sequence is telling us.
This sign from a Speedway station in western Michigan uses a fourth slot to indicate price for another item: cigarettes. Gas stations and smokes seem to go together better in MI than in CA.