The aim of this study is to explore the notion of stylistic hybridity in architecture by using shape grammar as a computational design methodology. The mid-twentieth-century architecture produced by William Hajjar is used as a case study for this exploration. Hajjar was a member of the architecture faculty at the Pennsylvania State University (Penn State), a practitioner in State College where the University Park campus is located, and an influential figure in the history of architecture in the area. The residential architecture he designed for and built in the area incorporates many of the shapes, rules, and features of both modern European architecture and traditional American architecture. Using computational methodology, this study offers an investigation into this hybridity phenomenon and explores the possibility of producing hybrid architectural designs for future uses. In the present study, shape grammars are used specifically to verify and describe the influence of Bauhaus/European modernism on Hajjar's domestic architecture: rules from the grammar developed for his single-family houses in the State College area will be compared with rules from the grammar developed for the Gropius-Breuer partnership in the United States. The potential of shape grammar will be discussed as an effective complementary tool for architectural historians to use in a mathematically rigorous way to verify the formal and functional similarities between styles. In short, it is proposed that shape grammars be used broadly in detective work to verify or disprove hypotheses
