Is S UPPLE ’s approach limited to dialog boxlike interfaces? Our approach of casting user interface design as a discrete combinatorial problem is particularly well suited for dialog boxlike user interfaces because there is a well-established vocabulary of interactions used for designing such interfaces. The approach is not limited to such interfaces, however. We hypothesize that it may also be possible to identify an analogous discrete set of basic operations for most canvas-based interfaces, such as word processors or image manipulation programs. We are encouraged by the results of a recent project that identified a vocabulary of 27 operations forming the foundation for most interactions performed on multi-touch surfaces [91].