1. A method of specifying tolerances for manufacturing an integrated circuit in silicon, the method comprising: automatically selecting, at least a group of circuit elements among a plurality of circuit elements in a design, if each circuit element in the group has a value of a design-specific attribute in conformance with a selected condition; automatically mapping the group of circuit elements obtained from automatically selecting to a plurality of shapes; and automatically storing at least an indication of the plurality of shapes, and associated therewith the design-specific attribute.