idealized...........................

      The school did not teach science but did give classes in freehand drawing and also technical drawing, a subject that provided Dirac with one of the foundations for his unique way of thinking about science. . . . Technical drawing, used by engineers to render three-dimensional objects on a flat piece of paper, is now taught at very few English junior schools, and rarely at senior level.  Yet, in the early twentieth century, it was a compulsory subject for half the pupils: for a few lessons each week, the class would be split into two: the girls studied needlework, while the boys were taught technical drawing.  In these classes, Dirac learned to make idealized visualisations of various manufactured products by showing them from three orthogonal points of view, making no allowance for the distortions of perspective.

-Graham Farmelo, The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom