A method for presentation of functional coverage includes representing a set of attributes of a design under test as a multi-dimensional cross-product space, which includes events corresponding to combinations of values of the attributes to be tested, the events including legal and illegal events. At least one test is run on the design, and responsively to the at least one test, a first group of the legal events that were covered by the at least one test and a second group of the legal events that remain non-covered after the at least one test are identified. One or more of the illegal events are grouped with at least one of the first and second groups so as to present a simplified model of the coverage of the events in the cross-product space.