The principle factor in my success has been an absolute desire to draw constantly. I never decided to be an artist. Simply, I couldn't stop myself from drawing. I drew for my own pleasure. I never wanted to know whether or not someone liked my drawings. I have never kept one of my drawings. I drew on walls, the school blackboard, odd bits of paper, the walls of barns. Today I'm still as fond of drawings as when I was a kid - and that was a long time ago - but, surprising as it may seem, I never thought about the money I would receive for my drawings. I simply drew them.