Apparatus includes a machine readable storage medium for storing a template library having at least one template. The template is to include a first layout representation of at least one pattern to be formed by multi-patterning a single layer of an IC. The pattern has a plurality of portions to be formed using a plurality of respectively different photomasks. The first layout representation includes data identifying on which photomask each portion is to be located. An electronic design automation (EDA) tool includes a processor configured to receive a hardware description language representation of at least a part of a circuit and generate a second layout representation of the part of the circuit having a plurality of polygons. The EDA tool has a matching module that identifies and outputs an indication of whether one or more of the plurality of portions matches a subset of the plurality of polygons.