Applications of Watt II function generator cognates

7R and 3RT3R Watt II function-generating mechanisms are examined and the existence of a double infinity of cognates are highlighted. For both the cases reference dimensional configuration mechanisms are defined which have a minimum number of parameters, these being considered best suited for performing a function generation synthesis. Overconstrained mechanisms are also shown to result from the merging of the input and output elements of two or more such function cognates. The practical cases of the rack-and-pinion and central-lever steering linkages are examined as planar mechanisms, and a maximum number of only three and four independent design parameters, respectively, are proven to exist.