In math and logic, an axiom is a statement that can be considered true without further proving. 2 + 2 = 4 is an axiom. As is the fact that every natural number n has a successor n+1.
“Axiomatic Codes” feature such statements as well. Any user interaction or any other change goes through one or more of these statements. Here is one way to achieve this:
This is the game “Snake”. Its main data structure defines in the Change enum any interaction that is possible: move right, left, or forward. and grow.
The Facing enum defines in what direction it might be facing at any given moment. North, South, East, and West