ABSTRACT
From time to time in the course of research in the field of technology a variant form is encountered which seems to violate accepted rules, especially the implicit idea that form is the concrete expression of efficient function. At the least the question arises as to whether the function of the tool or machine under study has been correctly understood and properly interpreted. At the worst one of the basic tenets of technology, namely that form and function are strongly linked, or, in its more extreme expression, that function determines form, seems to be invalidated. Such an object is the horizontal waterwheel of traditional Moroccan grain mills with its blades set at an angle to the vertical shaft that transmits power to the upper runner stone. This chapter is a reflection in particular on the problem set by this wheel, and in general on technological constraints, or the freedom of choice in technological processes.
