“Requirements are guesses. Designs are guesses. Estimates are guesses. What matters is how fast you can find out.” Mary Poppendieck “The problem isn’t that we don’t know how to build software. The problem is that we don’t know how to build software together .” Gene Kim Waterfall works very well when you know exactly what you are building. If you are constructing a house, pouring a foundation, or installing a system with fixed specifications, defining the work in detail up f