Larry Lousen lives and plays in Southern California, but his work breaths life onto the campuses of local high schools.“Been a good area for us,” said the owner of Boss Graphics, a company based in Los Angeles County that specializes in school murals.Indeed.Lousen’s artists returned to the City of Manteca on Tuesday afternoon to finish their latest project at Sierra High School.Billy Teichert and Kate Mauldin wore respirators as they applied a clear coat finish to the mural that faces Daniel Teicheira Memorial Stadium.They used rollers and a mechanical lift, carefully tracing the blue, black and silver lines they had painted months earlier.“The Den” stretches across the westerly wall of the small gymnasium. It features a howling mascot emerging from the cavity on the “D,” with the words: “Home of the Timberwolves.”From the football stadium, softball diamond or the practice fields at the farthest westerly reach of Sierra High, the graphic on the small gymnasium’s exterior wall dominates your sight line. “We figure schools will be here a longtime, so our designs are meant to be classic so they hold up with the design world,” Lousen said.