He’s not claiming the rewrite is a clean room implementation. In fact he’s explicitly saying it is not: > However, the purpose of clean-room methodology is to

He’s not claiming the rewrite is a clean room implementation. In fact he’s explicitly saying it is not: > However, the purpose of clean-room methodology is to ensure the resulting code is not a derivative work of the original. It is a means to an end, not the end itself. In this case, I can demonstrate that the end result is the same — the new code is structurally independent of the old code — through direct measurement rather than process guarantees alone.