The design process is best described metaphorically as a system of spaces rather than a predefined series or orderly steps. The spaces demarcate different sorts of related activities that together form the continuum of innovation (…) Design projects must ultimately pass through three spaces: inspiration, ideation and implementation. Projects will loop back through these spaces -particularly the first two-more than once as ideas are refined and new directions taken.
Brown, T., 2008. Design Thinking. In Harvard Business Review, June 2008, pp. 84-95