  The synchronization between two dynamical systems is one of the most
appealing phenomena occurring in Nature. Already observed by Huygens in the
case of two pendula, it is a current area of research in the case of chaotic
systems, with numerous applications in Physics, Biology or Engineering. We
present an elementary but detailed exploration of the theory behind this
phenomenon, including some graphical animations, with the aid of the free CAS
Maxima, but the code can be easily ported to other CASs. The examples used are
the Lorentz attractor and a pair of coupled pendula because these are
well-known models of dynamical systems, but the procedures are applicable to
any system described by a system of first-order differential equations.
