We define, explore, and demonstrate a new multitouch interaction space called "pin-and-cross." It combines one or more static touches ("pins") with another touch to cross a radial target, all performed with one hand. A formative study reveals pin-and-cross kinematic characteristics and evaluates fundamental performance and preference for target angles. These results are used to form design guidelines and recognition heuristics for pin-and-cross menus invoked with one and two pin fingers on first touch or after a drag. These guidelines are used to implement different pin-and-cross techniques. A controlled experiment compares a one finger pin-and-cross contextual menu to a Marking Menu and partial Pie Menu: pin-and-cross is just as accurate and 27% faster when invoked on a draggable object. A photo app demonstrates more pin-and-cross variations for extending two-finger scrolling, selecting modes while drawing, constraining two-finger transformations, and combining pin-and-cross with a Marking Menu.

Fundamental performance results for crossing-based selec-tion tasks with direct touch input are presented. A close adaptation of Accot and Zhai's indirect stylus crossing ex-periment reveals similar trends for direct touch input: touch crossing task time is faster or equivalent to touch pointing; continuous selection of large orthogonal crossing targets is most effective; and continuous selection of small collinear targets is least effective. Unlike indirect stylus and mouse crossing, not every kind of direct touch pointing perfor-mance is modeled accurately with standard Fitts' law. Instead, Fitts' law, used previously for touch pointing with small targets, is used to more accurately model discrete touch crossing with a directionally constrained target. In addition, visual touch feedback is shown to have a strong effect on absolute accuracy. Our work empirically validates touch crossing as a practical and efficient selection technique, and motivates the exploration of novel forms of expressive multi-touch crossing.