That process chart has some waterfall in it -- that's clear to see -- but the steps of those waterfalls are often done in a spiral manner (sounds confusing, it

That process chart has some waterfall in it -- that's clear to see -- but the steps of those waterfalls are often done in a spiral manner (sounds confusing, it really is). So you go down a waterfall in this chart, do some work, but you split the functionality of what you make into "blocks". The first block features the basic functionality. Subsequent blocks build on that. Really the DoD chart is what the DoD tells itself about how it designs and develops products, but in reality, it's even messier and more confused. It's the world's biggest exemplar of a spaghetti process.