“Cut Me Off,” an early standout from Perfect Shapes, the second album from art-rock songwriter Madeline Kenney, begins with an order: “Wait,” commands a mechanized voice at a crosswalk, counting down the seconds until Kenney can move. But at last, she lashes through the guitar lines that seem to have looped around her legs. “Don’t cut me off,” the North Carolina-via-West Coast singer counters, establishing rules of her own. By song’s end, she’s found her stride and momentum. “I gotta good thing going now,” she sings, backed by bright harmonies. The line is a personal affirmation, a way for Kenney to steel herself against distractions. But it also serves as a blanket statement for Kenney’s progress on , a set of 10 patiently simmering and ambitiously structured songs that offer a new image of self-assurance.