TDD applied twice is Red, Green, Refactor, Red, Green, Refactor. The only difference here is where the start/stop boundary is: Refactor, Red, Green, Refactor,

TDD applied twice is Red, Green, Refactor, Red, Green, Refactor. The only difference here is where the start/stop boundary is: Refactor, Red, Green, Refactor, Red, Green. Combining the two: (optional Refactor), Red, Green, Refactor each time.