An method and apparatus for forming wafers of varying thickness’. Each asynchronous flow is, on the other hand, associated to a respective indicative value of the delay to be recovered so that the respective queue has the right to be served and to another value indicating the instant in which the server visited the respective queue in the pervious cycle. Each input clock signal after the first has a phase offset of 2 \u03c0m from the previous input clock signal. The method includes regioselectively preparing a monomer that includes a pyridal2,1,3thiadiazole unit; and reacting the monomer to produce a polymer that includes a regioregular conjugated backbone section, wherein the section includes a repeat unit containing the pyridal2,1,3thiadiazole unit.