When thinking of Gary Burton’s collaborations on ECM, Chick Corea comes foremost to mind. But don’t forget this stirring 1975 record with Steve Swallow. Both musicians do double duty on keyboards (Burton on organ and Swallow on piano), thus shining the proverbial light through their creative prism from more angles than one might expect. The lion’s share is from the bassist’s pen, including the multivalent title track and the bittersweet “Sweeping Up.” Nods to Carla Bley (“Vashkar”) and Mike Gibbs (“Inside In”) sweeten the pot, making for a monochromatic gem in the vibraphonist’s otherwise technicolor discography.