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I went to www.ask.com and typed in that very question, which brought me to:

http://designinquiry.net/journal/failagain/87/neon-typography/

Somehow it lacks the exuberance today of, say, the 1953 Flamingo champagne tower, with its filigree of neon bubbles wrapping an 80 foot cylindrical tower by architects Pereira and Luckman, topped by six foot neon letters. It served no other programmatic purpose than to be looked at, and was thus the first “spectacular” on the Strip. (Design: YESCO)

Warning: The website covers a lot more than just the Flamingo sign, so be prepared to be pulled in...

Hope this helps...
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