As a thought experiment, he proposed developing a set of one-quarter-scale manipulator hands slaved to the operator's hands to build one-quarter scale machine tools analogous to those found in any machine shop. This set of small tools would then be used by the small hands to build and operate ten sets of one-sixteenth-scale hands and tools, and so forth, culminating in perhaps a billion tiny factories to achieve massively parallel operations. He uses the analogy of a pantograph as a way of scaling down items.