Design is the process of brain storming and putting ideas to paper. Gathering input and output requirements, selecting hardware and software. This is the first step in a product development for us, we try to identify any pipfalls and do as much research as possible. Next we move to the build step. Sometimes the build process has to get kicked back to design if things dont work out as planned. There are so many options and methods to get to a final established result that sometime going back to design is for cost or complexity.