Art instruction books often begin by stating “there are no lines in nature.” Which is obviously, annoyingly, both true and false. “Nature” may not have a horizon “line” drawn where earth meets sky, but people certainly perceive that line. As do their mechanical devices .

So beginners always start with lines. Kids outline flowers and houses in their first drawings. Stick figures, on the other hand, are abstract ideas of people like Mommy or Daddy with important bits – torso, limbs, and head – largely symbolic.

Shading is just as strange. Mostly we perceive shadows as darker shapes, but impressionists found them more real by adding colors .

The point of all this is that very little – even human basic perception – is quite as simple as it appears. This has been driven home lately by how much trouble computers have interpreting visual information like boxes in a pile .

Beyond that, things like lines and shadows require some concentrated imagination which is one of the reasons most of us like drawing and other visual arts. Not because it is “true” but because it is “fun” .

No lines in nature. An awful lot in our heads .