There are many teams that have very similar jersey colors to grass. Moreover, what is even more impressive, is there are some astroturf fields that aren't even

There are many teams that have very similar jersey colors to grass. Moreover, what is even more impressive, is there are some astroturf fields that aren't even green [1]! And the first down line works just fine on that as well. [1]: http://upload.wikimedia.org/wikipedia/en/5/56/Bronco_Stadium_September_25_2010.JPG http://upload.wikimedia.org/wikipedia/en/5/56/Bronco_Stadium...