Migos’ viral hit “Versace” was an exercise in advanced style: from a single word, this group built an entire song, one that makes much of today’s rap look lethargic by comparison. The trio’s stuttering, triplet-driven rhyme schemes are backed by a slew of productions by Zaytoven, one of Atlanta’s most original musical thinkers. His twinkling, slippery beats often resemble fragments of Bach blown apart and reconstructed with electronics. “Hannah Montana,” “Pronto,” and “Adios” demonstrate the pleasure of pure phonetics, where words are judged less by what they mean than by how fun they are to say.