Software development involves determining what to develop, documenting this decision, determining how to develop it, and actually developing it.We present a framework for describing this process in terms of layers of activity. Many people use pyramid analogies, which show the magnitude of effort in each layer (lines of code versus lines of requirements, for example). Many other people use inverted pyramids to reflect the importance (or impact) of work done at different layers (a sentance defining a strategy has more impact than a line of code). Some people show PERT diagrams of waterfalls or pretty circular arrows charts showing iterative lifecycles, or any of many good analogies.