Richard Thompson, a Washington-based cartoonist, has been a regular contributor to The Post for some 20 years. Every Saturday, you can find "Richard's Poor Almanack" in Style. Thompson is also the creator of a recently nationally syndicated comic strip, "Cul de Sac," which originated in The Washington Post Magazine. In "Drawing a Funny Cartoon," he reveals his creative process, which is based on endless doodling, staring vacantly into the middle distance and fear of an impending deadline. The part about Toulouse-Lautrec on a flying pig is pretty much true.