Technical Report Number
Visual programming is the specification of computational processes using diagrams and icons. Traditional computation models such as Turing machines and lambda-calculus, which are based on one-dimensional text strings, are not suitable for visual programming languages. We propose a two-dimensional computation model that requires no text. We also prove that the model is computationallhy complete, i.e., that the model has the same computational power as Turing machines.
Brown, Timothy B., "Completeness of a Visual Computation Model" Report Number: WUCS-93-53 (1993). All Computer Science and Engineering Research.