Named after the keystroke for making a delta (i.e., triangle) sign on a Mac by holding down the Alt and J keys, the Leeds, Englandâbased trio alt-J is inspired by the symbolâs mathematical definition of change. This makes sense upon hearing the bandâs handsome 2012 debut album, An Awesome Wave. Its take on postmodern pop mines the best elements from folk-rock, garage rock, dub-pop, indie rock, vintage cinema scores, and a cappella harmony before constructing layered, angular arrangements with sonic ore. Following a dramatic piano part, the opening âIntroâ weaves heavily reverberated baritone guitar leads (Ã la Ennio Morricone) over and around looped beats and random vocal samples that all come together to play like the sons of The Beta Band. These contrast the pointed, geometric arrangements of âTessellateâ with Joe Newmanâs flowing, throaty vocals and backing harmonies, which hover above the music like those of Fleet Foxes. Then, in âBreezeblocksââa mechanically grooving standout in which a toy piano provides the leadâhe inflects like Devendra Banhart imitating Jason Mraz, with overt affectation. âHand Madeâ closes with folky minimalism.