“Painted canvas and standing plaster figures no longer have any reason to exist,” said Lucio Fontana. “What is needed is a change in both essence and form.” His change in essence and form was cutting edge—literally—and revolutionary. Fontana slashed his canvases, wielding the knife with precision and power. Something between art and act, his creations combined elements of sculpture, painting, and performance. Fontana’s friend Ugo Mulas, a photographer, would sometimes visit and snap photos of him while he worked. The images capture an atmosphere of solemnity. In a rare display, Mulas’s photographs and Fontana’s Concetti Spaziali are on view side by side. The two men are in the same room once more. —E.C.