These are all text-davinci-002, temperature=0 without cherry-picking. It works because I say "Let's think step-by-step" as verbosely as possible to demonstrate the desired style. Also the prompt extends three words into a new paragraph to clarify the style persists.

This is "leading the answer" — filtering the answer space to a higher-quality subset. It's the same idea as using triple-backticks when requesting code output: If you know how a good answer begins, include it.