A double pendulum is a pendulum with another pendulum attached to its end, and is a simple physical system[?] that exhibits rich dynamic behavior[?]. The double pendulum is governed by very complicated formulas that can be found here (http://scienceworld.wolfram.com/physics/DoublePendulum). The double pendulum relates to:
... 28.2% from 45 to 64, and 20.7% who are 65 years of age or older. The median age is 44 years. For every 100 females there are 93.5 males. For every 100 females age 18 ...