4:3. 16:9. 1.37. 1.85. Academy ratio. 2.20. 2.35. Letterbox. Pillarbox. Cinemascope. Anamorphic. And so forth and so on.

Throughout the history of projected and broadcast visual entertainment, aspect ratios - that is, the ratio between how wide an image is compared to how tall it is - have constantly changed.

And, if you've ever sat in your parent's living room, trying not to rip the TV remote from their hands as you wonder how they can possibly stand to watch everything zoomed and stretched on their flat screen TV, you'll understand just how frustrating it can be to not see something in its proper aspect ratio.

In this excellent video entitled "The Changing Shape of Cinema: The History of Aspect Ratio", John Hess traces the evolution of the screen shape from the earliest days of silent films all the way up to modern movies and broadcasting.

Fascinating stuff for any fan of movies and TV. Enjoy!