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:
... subscribers could view it. In 1999, with the advent of digital television in the UK, satellite viewers were able to view the service.
The BBC were initially criticized ...