Peruvian artist Alberto Casari’s 15-year retrospective (“Alberto Casari & PPPP, 1993 -2008”) , showing at the downstairs ICPNA gallery through May 18 (see gallery listing below), teases the limits of what’s considered Art in conservative Lima. The wide-ranging exhibit showcases, among other objects, a chair impossible to sit on, blank canvases “painted” with ocean water, a pair of rubber diving fins decorated with eyes, and a boiling pot set on a stovetop, which, upon closer inspection, turns out to be a pan of condensed ice kept solid through refrigeration. Even more titillating is a photo triptych of a gaudy birthday cake decorated with the text, “La Madre de los Conchasumadres…