Sign is trim and rich and has something like a face. It wants to be an album. It reacts well to being played over and over. The difference isn’t obscure—it’s the presence of melody and harmony, variables the duo hasn’t paid attention to in ages. Almost every track on Sign works around some relationship between pitches and an audible line of progression. It feels as if they are pulling us back into their orbit just as they are pulled back into it. Sign flirts with disintegration but only lightly, throwing its weight into a smooth ravine lined with translucent panels and reflective tape, a river of light running below the wind of a thousand turbines.