Seems to contradict this statement: > When unsafe code is written, it can be shown that it "works", but this takes effort and engineering time. When things are

Seems to contradict this statement: > When unsafe code is written, it can be shown that it "works", but this takes effort and engineering time. When things are designed such that they cannot fail, it doesn't take effort and engineering time to make sure they "work". This is why designing from the beginning with correctness in mind is superior than writing crap code and then debugging later.