> It's the design that is the hard part Design but also requirements. You don't really know what should be built until you have a prototype. And estimating how

> It's the design that is the hard part Design but also requirements. You don't really know what should be built until you have a prototype. And estimating how long it will take to come up with a prototype that does what you think it should do, in other words coming up with requirements, is just the snake eating its tail.