Attention is being given to improving the design of undergraduate gateway courses (i.e., entry-level, introductory) in the fields of science, technology, engineering, and mathematics (STEM), particularly those facing challenges of large enrollment and high failure rates. Effective course design has been noted as a key strategy for improving the quality of higher education teaching. The science of design has a goal of studying how people design, what they design, and what knowledge is drawn upon during design work. This embedded case study systematically investigated how faculty design knowledge influences design practice. Three faculty individually participated in a 6-hour course modeling workshop and used the Learning Environment Modeling (LEM) toolkit to generate 13 visual lesson blueprints while engaging in design discussions and interviews. A two-phased, hybrid inductive-deductive analysis approach was used for data collection, data preparation, and data analysis. Results discuss the (1) the variety, frequency, and distribution of lesson elements in visual lesson blueprints, (2) six "design patterns of practice" emergent among activity sequences and lesson sequences; (3) the 18 contextual factors that influence STEM faculty design decisions, and (4) granularity and scale as two key influencers to faculty design knowledge and design practice. The findings of this study contribute to existing literature on STEM faculty design knowledge and design practice examined through visual lesson blueprints and design toolkits. The study offers implications to qualitative and visual research methods as well as to university centers for teaching and learning as key stakeholders in supporting faculty as designers.