For Lady Gaga, imagery is as vital as sound, especially when it comes to the art of subversion. Her pop comes fully formed when she slips into sky-high platforms and flirts with blasphemy ("Alejandro"), dies from fame ("Paparazzi") or commits mass homicide with Beyoncé ("Telephone"). Just as comfortably, she can incite a riot in some simple cut-off denim ("Perfect Illusion").