|Date||Oct. 21st 2011|
Prairie is the 967th xkcd comic.
This is a reference to the wave-particle duality of matter. One interpretation of quantum physics states that light, when observed, acts as a particle, but when unobserved, acts as a wave.
"Colorado is working to develop coherent amber waves, which would allow them to finally destroy Kansas and Nebraska with a devastating but majestic grain laser."