"I would draw at night while riding - Even though I carried a sketch pad small enough to be hidden by the seat back in front of me, people, especially women, would often sense that they were being observed, get up and move to another seat. Persons seated across the aisle, to my left and facing me, would be reflected against the night in the seat windows to my right.

"I decided to draw these images instead of the living 'models,' and this subterfuge made it appear that I was merely looking out the window. The riders no longer felt threatened by direct observation."

- Robert Guinan


http://www.bigredhair.com/robertguinan/article.html