The SlyPhone Camera Periscope is an inconspicuous, surreptitious way to take a photo of something or someone without them noticing you snapping way.
Designed by James George and Alexander Porter, the mirror fits on to any iPhone 4 or 5 device and acts as a periscope, similar to designs employed by submarines. Instead of having to peer straight ahead and lift your camera together, however, the SlyPhone Camera Periscope is intended to "reverse our culture of surveillance" and turn every person with a phone into a documentarian. Priced at $19, the periscope fits over the front facing camera and reflects a picture of what's in front without you having to make direct eye contact with the subject.
As such, the Slyphone Camera Periscope is intended for a tool of "social critique," while letting you return to your game of Candy Crush quickly should the subject notice anything fishy.