I guess more succinctly it would be like 1) Design mockups showing workflow for feasible idea 2) Sell feasible idea 3) Design architecture for feasible idea

I guess more succinctly it would be like 1) Design mockups showing workflow for feasible idea 2) Sell feasible idea 3) Design architecture for feasible idea 4) Build feasible idea At each new level of these you are asking more and more specific questions about how it would work and are getting "closer to the metal", with the final step being the implementation of EVERY detail (that is known, at least). Also at each step, you discover new things you didn't think to think about, but now must deal with... it's a discovery process. But this is great because it puts the focus on "gauging interest first" before you spend weeks building anything.