Over the years, one of the interesting things I have noticed about drawing is that, quite apart from what you are intending or thinking as you draw, it can vary in appearance based upon the mental state of the artist.

The most familiar example for me is doodling while on the telephone. I imagine everybody has done that, at least occasionally, but (at least in my case) I have noticed that once my conscious control is lessened by the mental processing of speech, inhibitions are removed and some odd and fanciful things appear on the page -- things that I might never have drawn otherwise.
