Gestures are a limited size and duration pen-tip trajectory of unique shape, mostly (but not exclusively) different from known character shapes. A problem is the discrimination between character shapes from gesture shapes, both by recognition algorithms on the CIM side, and by the human user (Cognition and HOC side), who must remember the pattern shapes and their meaning. Ideally, a pen-based user interface is ``mode-less'', but often a gesture mode must be invoked to address the gesture recognizer explicitly. Also, the gestures can be produced in dedicated screen areas. Two different basic pen gestures may be defined: