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:
... household size is 3.03 and the average family size is 3.38.
In the town the population is spread out with 28.5% under the age of 18, 6.3% from 18 to 24, 32.3% from 25 ...