A Few Stray SXSW Thoughts The best lost-love song with advanced-physics puns has to be "Redshift" by Darwin Deez, whose mission as a songwriter seems to involve merging the guitar-scrubbing light funk of the 1970"s with the musicianly twists-gnarled harmonies, leaping and twisting melodies-of Frank Zappa. "You loved all of my little quarks, so what went wrong?/Don't superstring me along," he lamented in a semblance of an R&B ballad. Wave or particle, I can't be both. Does enjoying hip-hop require understanding the words? Not with Emicida, a Brazilian rapper from Sao Paulo. He gave a few clues in English to what his songs were about: peace, love, defying the system. But his rhymes are in Portuguese, and what made the songs work was the way they bounced off the music, in cadences that sometimes sounded like hip-hop in English but also had the briskness of the quick lyrics in upbeat Brazilian pop. The grooves, delivered by a small group including a guitarist, a DJ and Emicida on a sampler, juggled and mingled funk with Brazilian rhythms like forro and maracatu and Emicida kept changing up his tone: accusatory or affectionate, buttonholing or casual. There weren't a lot of people in the room on Wednesday night, but hardly any of them could resist dancing. Dance-pop music loves a woman scorned, and the English singer and songwriter Charli XCX is more than willing to step into the role. She collaborated with Icona Pop on the irresistible "I Love It," but her own songs are more elaborate, and sometimes blunt to point of profanity, in their denunciations of guys who tried to get away with too much. She has happier songs too, but even in those, romantic tension can be literally earth-shattering, as it is in "Nuclear Seasons." Onstage at SXSW, backed by recorded tracks and a drummer, she danced up a storm in towering platform shoes, belting thoughts of revenge and passion. Her production choices have moved from brittle electronics to booming, chiming pop, and she's got her archetype well under construction.