A system and methods for progressive feature evaluation of an electronic document image to identify user supplied elements is disclosed. The duplex local oscillator signal and the radio frequency local oscillator signal are mixed to provide a converted radio frequency local oscillator signal, which is then provided for output. The hands and fingers are in the pianist position and produce finger-taps organized in groups of simultaneously occurring taps called combinations of concurrent fingers-taps. For each particular code statement, the process generates predicate statements that describe an effect that the statement has on the predicates of interest.