There are a million iPhone cases in the world it seems. Some are beautiful, some are solar-powered, and some add a kickstand, but few are actually fun. Case Mate’s new Quartet and Stacks iPhone 4 cases inject a bit of fancy (as well as customization) into the market. Both cases are made up of interchangeable pieces that users can arrange how they like (for the most part), then rearrange when they want to change things up. The Quartet, as the name suggests, gives users four pieces at a time to work with — each package has 6 total. The Stacks comes with 6 vertical bands that snap together. Case Mate sells each in various palettes. The more you buy, the more customization options you have at your fingertips.