Louis Kahn used to tell his students: if you are ever stuck for inspiration, ask your materials for advice. In the image, the point of view is the loop screwed into the wall. The string is a ray of light reflecting from the lute to that point of view. The apprentice holds the point on the lute that is to be drawn, and also holds the drawing itself away from the frame. The artist is marking the location of the point of intersection between the ray of light and the picture plane. On the drawing in the hand of the apprentice, we can see the foreshortened image taking shape, with geometric precision, dot by dot.
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Representing a Weighted Graph with an adjacency matrix in JavaScript post 
by Regina Furness
Ask architects what they do: they'll share lofty stories and philosophy. Louis Kahn told us to ask a brick what it wants to be. Watch what architects actually do: all of them draw. They draw, doodle, trace, and draw, and draw, and draw some more.
"Man Drawing a Lute", woodcut by Albrecht Dürer (1525) Location: Metropolitan Museum of Art, New York wikipedia 
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