If just one thing can be confirmed from these compelling Tiny Desk performances by the Calidore String Quartet, it should be that the centuries-old formula – two violins, a viola and a cello – is still very much alive and evolving. Indeed, an impromptu show of hands in the audience before the concert began revealed that almost everyone had seen a string quartet perform live. The genre was born some 250 years ago and pioneered by Joseph Haydn, but composers today are still tinkering with its possibilities. Consider Caroline Shaw. The young, Pulitzer-winning composer wrote the opening work in this set, First Essay: Nimrod, especially for the Calidore String Quartet. Over a span of eight minutes, the supple theme that opens this extraordinary work takes a circuitous adventure. It unfolds into a song for the cello, is sliced into melodic shards, gets bathed in soft light, becomes gritty and aggressive and disguises itself in accents of the old master composers. Midway through, the piece erupts in spasms that slowly dissolve back into the theme. The Calidore players also chose music by the quirky Czech composer, Leoš Janáček who, in 1913, set one of his operas on the moon. He wrote only two string quartets but they are dazzling. The opening Adagio, from his first quartet, is typical Janáček, with hairpin turns that veer from passionate romance to prickly anxiety. Reaching back farther, the ensemble closes the set with an early quartet by Beethoven, who took what Haydn threw down and ran with it. The final movement from Beethoven's Fourth Quartet both looks back at Haydn's elegance and implies the rambunctious, even violent, risks his music would soon take. The performance turns out to be a fascinating through-line, traced from Beethoven's early incarnation of the string quartet, straight through to Caroline Shaw's new sounds, which occasionally glance backward. SET LIST Caroline Shaw: "First Essay: Nimrod" Janáček: "String Quartet No. 1, 'Adagio'" Beethoven: "String Quartet Op. 18, No. 4, Allegro - Prestissimo" MUSICIANS Jeffrey Myers, violin; Ryan Meehan, violin; Jeremy Berry, viola; Estelle Choi, cello CREDITS Producers: Tom Huizenga, Morgan Noelle Smith; Creative Director: Bob Boilen; Audio Engineer: Josh Rogosin; Videographers: Morgan Noelle Smith, CJ Riculan; Production Assistant: Adelaide Sandstrom; Photo: Amir Alfiky/NPR