In the context of this paper it is interesting to remember that Rosenblatt's perceptron in the 60s was implemented in hardware with potentiometers for weights,

In the context of this paper it is interesting to remember that Rosenblatt's perceptron in the 60s was implemented in hardware with potentiometers for weights, tuned by stepper motors. https://en.wikipedia.org/wiki/Perceptron#History https://en.wikipedia.org/wiki/Perceptron#History