https://en.wikipedia.org/wiki/Rule_of_three_(computer_programming) https://en.wikipedia.org/wiki/Rule_of_three_(computer_progra... lines up better with my exper

https://en.wikipedia.org/wiki/Rule_of_three_(computer_programming) https://en.wikipedia.org/wiki/Rule_of_three_(computer_progra... lines up better with my experience: postpone writing the abstraction until you are actually implementing the third thing. With just two cases, there will generally be a bunch of incidental commonalities that are better left out of the abstraction, and it's frequently not obvious which ones they are.