Katy Perry’s “Prism” comes out a week from today, but while you’re waiting to hear her “Roar,” you can listen to 90-snippets of each of the 13 songs above and beyond the handful we’ve already heard: “Roar,” “Dark Horse” and “Walking On Air.”  We've embedded them in for you instead of making you go to ITunes, so it takes a second to load up, but then just press play and enjoy.