[mcguire]

The "depth-first" approach (I've seen it as well) is a mistake that is largely orthogonal to a top-down/bottom-up style. It looks top-down, but immediately goes off into the weeds and can easily be recognized by statements of the form, "I need an X, so I'm building a Y." As in, "I need a reporting application, so I'm building a logging module", or the '90s Japanese 5th generation computing project, "We need intelligent, communicating systems, so we'll build a Prolog machine."