Every now and again, I'll post a cartoon suitable for tacking up on a bulletin board, or blending into an economics lecture. This one is from back in 2008, from Dale Everett at the Anarchy In Your Head website, but I just saw it for the first time, so I pass it along.
Addendum: A helpful reader points out that a similar comment was attributed to Ronald Coase by David Landes, who said in a 1983 symposium published in the Journal of Law and Economics: "Ronald said he had gotten tired of antitrust because when the
prices went up the judges said it was monopoly, when the prices went
down, they said it was predatory pricing, and when they stayed the same,
they said it was tacit collusion."
The citation is Edmund W. Kitch, "The Fire of Truth: A Remembrance of Law and Economics at Chicago, 1932-1970," Journal of Law & Economics, Vol. 26, No. 1 (Apr., 1983), pp. 163-234. Quotation is on p. 193.