Now an organization has created a “new” Nirvana song using artificial-intelligence software to approximate the singer-guitarist’s songwriting. The guitar riffs vary from quiet, “Come as You Are”–style plucking to raging, Bleach fury à la “Scoff.” And lyrics like, “The sun shines on you but I don’t know how,” and a surprisingly anthemic chorus, “I don’t care/I feel as one, drowned in the sun,” bear evocative, Cobain-esque qualities.