This paper examines the role of design concepts in a modus operandi as opposed to a modus operatum, which is how their generation, as it unfolds over time, is perceived by someone involved in designing instead of with the hindsight of being finished. To this end, the interactive activation and competition model, commonly used to model the retrieval of information from stored knowledge of individual exemplars, is applied in the context of architectural design. Parsing the data of an architect's think-aloud protocol through this model at successive points in the design process results in a photo shoot of a design concept “under construction.” This allows for the start of appreciating and accounting for the highly elusive character of concepts during design.