[andsmedeiros]

I don't think the quote suggests that a programmer would mentally design a whole system before writing any code. As programmers, we are used to thinking in problems as steps needing resolution and that's exactly the 90% there. When you're quickly prototyping to see what fits better as a solution to the problem you're facing, you must have already thought what are the requirements, what are the constraints, what would be a reasonable API given your use case. Poking around until you find a reasonable path forward means you have already defined which way is forwards.