From its upside down cover photo to the off-kilter music inside, Grande’s fourth album is clearly meant as the ponytailed pop singer’s Mature Artistic Statement. The quirkier tracks come courtesy of singer-rapper-producer Pharrell Williams, of “Happy” fame, while the more straightforward offerings are the work of Swedish hitmaker Max Martin. Grande makes no direct reference to the terrorist attack at her May 2017 Manchester concert that killed 23 people and injured another 500, although one bubbling, infectious Williams number has Grande half-rapping “The light is coming to give back everything the darkness stole.” She addresses her clinical anxiety on “Breathin’” and “Get Well Soon,” the latter featuring swooping doo-wop harmonies and swirling synthesizers. And Grande even name checks her comedian fiancé in the ultra-sweet “Pete Davidson.” But when it comes to experimentalism nothing tops the dreamlike “R.E.M.” and the cowbell-laced “Borderline,” where she and Williams revel in delightful weirdness. For the usually demure Grande, it’s a welcome change.