William Turner, Tracing of a Perspective Construction of a House, 1810.
For complex lecture diagrams [Turner] normally first carried out a very careful pencil and ink drawing, based on a detailed perspective construction. He then traced the outlines of the drawing and added a simplified version of the main details of the construction to give the lecture diagram. He sometimes enlarged the tracing, possibly using a pantography, or possibly the eye. Even in the latter case he normally kept the viewpoint in exactly the same position.