Airplanes, automobiles and Seinfeld created American crazes—and brought two-toned bread along for the ride. “Marble” or “marbled” bread usually refers to rye bread with a yin-yang swirl of light and dark. Two breads in one—what a luxury. It makes Reubens more Reubenesque. It draws us in with that hypnotic spiral. Seinfeld elevated a braided version of this deli specialty to an object of adulation and obsession in “The Rye” episode. But a two-toned bread made of wheat generally just gets called “spiral.” Although it looks like marble rye and could probably substitute for it, hardly anyone calls it “marble wheat.” Double Take Bread Years ago, someone made a valiant attempt to give spiral whole…