Before Burger Madness, there was mural madness at Arthur’s, the Hyde Park restaurant/bar. From 1981 to 1992, Jerry Dowling painted caricatures of 142 regulars on a 44-foot wall. The characters are still there — on the mural, anyway — but the character has changed. Customers who enjoyed happy hour then come for hamburgers today, grandkids in tow. But preserved by cigarette and beer stains, as Dowling half-jokes, the mural is a memory of fun, foolishness and figuring things out.