It’s one thing to fashion your own style, but Autechre's abstract take on electronic music is the equivalent of inventing your own musical language: a bewildering array of digital sounds that rain down like a screenful of code, as beautiful as they are mercurial. The Sheffield, UK duo began simply enough: In the early ’90s, Sean Booth and Rob Brown were just a couple of B-boys emulating their favorite electro tunes on a drum machine and sampler. Their debut album, 1993’s Incunabula, found common cause with the skittering beats and mournful synth melodies of the nascent IDM scene, and successive releases pushed the sound forward by adding further kinks to the rhythms, additional crinkles to the synthetic textures. By 1998’s LP5, their granular timbres and shape-shifting grooves had left most of their contemporaries in the dust, and they have only continued down that same arcane path. Part of the strangeness of Autechre's work owes to the fact that they don’t so much compose music as endlessly tinker with a shared set of software patches until instinct dictates that the track is finished. That infinitely iterative approach comes to the fore on 2018’s NTS Sessions, a four-album, eight-hour set (put together for London’s NTS Radio) that is their most thrillingly cryptic work yet. It’s some of the most challenging listening ever to come out of dance music culture—and some of the most rewarding too.