The thermostats on the colony ship Arkwright didn’t use numbers like 98.6 or 100.2. They used a ternary system: cold (0), nominal (1), and hot (2). But every engineer knew about the ghost digit.
In assembly-line style restaurants (e.g., vegan cafes or hot pot spots), "base 3 hot" may refer to a meal deal allowing for 1 base and 3 hot dishes . base 3 hot