Disclosed is a method for identifying a number of interactions with a computer input area defined by at least first and second intersecting sets of detection paths. First, indications of which of the detection paths are affected by the interactions are received. Then, for each of the detection path sets, the set's indications of affected detection paths are parsed to identify up to N extents of adjacent, affected detection paths (N≧2). A controller having logic to implement the method, and a system incorporating a control system that implements the method, are also disclosed.