The circuit layout problem is an important and difficult problem of computer system design and is encountered in laying out subpackages (e.g. PCBs and integrated circuit masks), where the terminals of a set of components placed on a subpackage are to be interconnected by laying printed wires. The specific set of pins (i.e. terminals) to be made electrically common by printed wire constitutes a single net. Realization of multiple nets on the surface of the PCB is classically termed as ‘Interconnection Problem’ by Hightower (1974) which consists of five sub problems—(i) pin assignment, (ii) Steiner-tree identification for a net, (iii) layering of the wires, (iv) ordering and (v) physical identification of wire path on a PCB. An exhaustive survey on all these subproblems is available in the book edited by Breuer (1972) and survey papers of Hightower (1974), Bose (1977). In this paper, we concentrate on an up-to-date survey of the last sub problem (i.e. wire routing of PCBs). We group together the wire-routin...