Cambridge's Professor Raymond Goldstein told Reuters that he and his colleagues took account of the stiffness of individual hairs, the effects of gravity and the average waviness of human hair to come up with their formula.

The Rapunzel Number provides a key ratio needed to calculate the effects of gravity on hair relative to its length. That determines whether the ponytail looks like a fan or whether it arcs over and becomes nearly vertical at the bottom...

Scientists from the University of Cambridge and the University of Warwick said they had devised a "Ponytail Shape Equation," which when calculated using the Rapunzel Number and a measure of the curliness of hair can be used to predict the shape of any ponytail.

source http://uk.reuters.com/article/2012/02/10/us-science-hair-rapunzel-idUKTRE81918V20120210

I wonder what does a stylist do in their salon? How to create, inspire, live fashion? Today I interpret German French & English into Greek for Redken "Learn better Earn better Live better" by L'Oreal "Because I'm worth it" in Berlin. 

Thousands of salon professionals from around the world have experienced the energy, excitement and education that embodies this event. In 2012, for the first time ever, the energy from the Redken Symposium will travel to Europe. The German Redken Team is proud and honored to host the first ever Redken European Symposium, February 12-15,
2012, in the former airport of Berlin, Tempelhof.

http://redkenevents.co.uk/euro-sympo/