In the stark black-and-white trailer for her seventh solo album petal rock black, WILLOW described its creation as equally nerve-wracking and inspiring. For a year and a half, the singer and instrumentalist challenged herself to write, play, and record completely alone but for her engineer, Adam Schoeller, seeing what sounds emerged when no one else was around to hear them. The resulting songs are the most experimental of the 25-year-old musician’s career, a free-wheeling blend of art pop and spiritual jazz that draws from Alice Coltrane, Joni Mitchell, and Dirty Projectors. With simple, meditative lyrics steeped in Buddhist scriptures, WILLOW embarks on a quiet journey deep inside herself, concluding on “not a fantasy”: “I am enough/I don’t need no more.” Besides an acclaimed trio of guests—Tune-Yards’ Merrill Garbus, jazz saxophonist Kamasi Washington, and a spoken-word poem from George Clinton—every sound you hear on petal rock black is WILLOW’s alone.