It would be an app for golf, the sport. You would take your phone, put it on a tripod and you would hit lets say 30 shots, meanwhile the program would take each shot you hit and analyze what movement you have done. With object recognition. Then it would analyze the average mistake and it will compare it with a good shot from a good player and then it will find your error. And give you preloaded tricks on what you could do to fix this. It would have to analyze movement. Calculate average, find mistakes, differences, etc. Most basically it is all about angles, of body, and club.