In logic, we call the things in the universal model valuations; they are Boolean-values functions defined on the set of predicates.

In computer science we often call these states, because, as we will see later, they are often used to represent states of a computing system.

We picture a system as a black box with a number of lights that tell the state of the system. A simple example is a traffic signal with three lights, red (R), green (G), and amber (A). Traffic lights in the UK cycle through four states: R; RA; G; A; R.

We use four lights, amber, green, red, blue, to present a 4-bit Karnaugh Map. A Karnaugh map represents a system in which changes only one light at a time. States that differ in only one bit are adjacent in the Karnaugh Map>

This video introduces the four-bit Karnaugh Map.