From my sketchbook 10 years ago, digitally enhanced for sharpness. I like it most for its simplicity which may to some extent conceal my lack of drawing ability. The intent was to have the viewer initially see it as a potentially real structure, then on further inspection realize that it is not possible. You can see from the upper left corner, I was thinking of the pythagorean theorem at the time that I drew it, but it played no part in producing the drawing.