https://en.wikipedia.org/wiki/Idea–expression_divide https://en.wikipedia.org/wiki/Idea–expression_divide > A broader but related concept is the merger doctrin

https://en.wikipedia.org/wiki/Idea–expression_divide https://en.wikipedia.org/wiki/Idea–expression_divide > A broader but related concept is the merger doctrine. Some ideas can be expressed intelligibly only in one or a limited number of ways. The rules of a game provide an example. In such cases the expression merges with the idea and is therefore not protected.