Out of the mysterious variables of love came David Auburn's Pulitzer Prize- and Tony Award-winning Proof, a play about familial love, genius and the terrible effects of madness on family. And for a brief two weeks Proof came to Houston, where it glowed at the Wortham Theater with a thousand megawatts of intellectual power. Rarely does a nonmusical drama garner so much success that it earns a national tour, but Proof provided that sizzling combination of wit, whodunit suspense and tender heart that continues to make live theater feel vital.