> Yet they are robust - all the bugs in the commonly traficked code paths have already been sussed out, and from outside the software looks like an impenetrable

> Yet they are robust - all the bugs in the commonly traficked code paths have already been sussed out, and from outside the software looks like an impenetrable, rugged piece of craftsmanship. I disagree. I think they only feel robust. I think more importantly this mode of development is defensible and always gives one something concrete in the case of being asked "so what's the product of this 3 days of work?".