Hewer, your example matches "Practical Uses of the Steel Square" by Fred Hodgson. This method is unlike the common methods of defining PITCH, such as rise over run or rise over span, instead he uses a method of dividing the arc of the quadrant, a method of angular description which will not agree with the rise over span or the rise over run methods. It is an absurd idea that tells the world that it is wrong and Hodgson knows the exact way. Very strangely, everything that follow in the Hodgson text refutes this method.