Last year, Lupe Fiasco set himself apart from the rap pack with a debut full of brainy, Kanye-style positivity, including a laid-back skateboarding anthem, ''Kick, Push.'' You might wonder what happened to that guy if you've read how his follow-up, The Cool, is a concept album about gangsta life. But in truth, only four songs address that story line - thankfully leaving the bulk of this CD to instead indulge in Fiasco's divergent themes and musical explorations.