A geometric model, termed an H diagram, is an effective visual aid in the synthesis of combinational logic circuits. The model is derived by means of coordinate transformations of a hypercube, resulting in a simple two-dimensional framework for mapping a binary function. The H diagram can be expanded to accommodate an arbitrary number of variables, while maintaining a mathematically consistent pattern that permits the extension of simple geometric interpretations to problems of more complexity. The effectiveness of the H diagram is demonstrated by applications that include the selection of prime implicants, expansion about arbitrary subfunctions, and transformation of variable sequences.