Think you’ve exhausted every possible dance formation? Give your brain a break and let this app do the thinking for you. Dance Formations Plus! shows you six different formations—with built-in “windows”—for each of your groups of 5 to 18 dancers, for a total of 84 formations to choose from. (Brooklynettes dance team coach Adar Wellington is a fan.) You can also create your own custom formations and save them to a folder (iPad version only).