Further proof of "head and eyes"... Truly your best friend on a bike.
Excuse my crude 30 second rendering, but this is called the "keyhole". It's part of the class and one of the things you have to successfully complete to pass the class. I'm not certain of the 16' measurement, but 95% sure.
You have to ride in, and out, without putting your feet down or knocking over cones. The world's hardest u-turn [smiley=laugh.gif]
If you were to walk your bike into the keyhole using the best angle possible, lock the handlebars, and attempt to push it thru, it would not fit. The bike cannot physically fit thru it. [smiley=confused5.gif] But for some reason, if you ride in, look behind you, and keep your head and eyes aimed at the entrance, you CAN fit and get out. Keep your head and eyes aimed where you want your bike to go!!! [smiley=beerchug.gif]