Game designer Raph Koster presents a hierarchical taxonomy for describing what games actually are (and, consequentially, what they are not).
- A Game is a unique rules construct.
- A Reskin is a superficial change in presentation of an existing rules construct.
- A Variant is a minor mechanical deviation from an existing rules construct.
- A Family is a set of Variants.
- A Genre is a set of Reskins and their Variants.
Almost every video game made today is actually a Variant rather than a unique game, in contrast to board games which are more often than not entirely new rules constructs.