Artist Ron English took skywriting to a whole new level when he wrote the word "cloud" five times over Manhattan and let the words slowly become clouds. Lest you think Mr. English is one of those "artists" who thinks doing something a little strange makes you an artist, I suggest you view the gallery on his website --just a warning though, some of his paintings may not be SFW.
Link Via Laughing Squid
Vic Muniz did a similar piece years ago in 2001. http://www.creativetime.org/programs/archive/2001/clouds/muniz/index.html
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