Here's how I have mine run:

This way you use the whole cable on the rack. For my bigger girls I run the cable (in the same pattern) but up to the top (white line in picture) to make a larger warm spot for them - but need to add an extra 10 foot piece to do this.
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Tosha 
JET Pythons
(CJBianco explaining the origins of the BP market.)
"In the beginning Bob created the Ball Python market. And the market was without morph, and wild traits were upon the industry. And Bob said, Let there be morph, and there was morph. And Bob saw the morph, that it was good; and Bob divided the morph from the wild trait. And Bob called the morph Albino, and the wild trait Normal. And the Albino and the Heterozygous Albino were the first investment.
-- Christopher 1:1-1:5"