Huygens' synchronization : a challenge

Oscillations are common almost everywhere, be it in biology, in economics, in physics and many other fields. Everyone is familiar with the day-night rhythm, or the regular or less regular heart-beat of a human, the pig cycle in economy or the flashing of fire-flies and so on. All the above examples have in common that the oscillations seem to happen naturally, but there are also other more or less forced type of oscillations like for instance in chemistry, electrical circuits and acoustics. Probably the most basic example of an oscillator is a pendulum clock that runs at a fixed frequency and such that the exact time is given by the clock. Design and construction of a fully accurate mechanical clock is – even today – a very challenging task; the reader is referred to [Rawlings, 1994; Penman, 1998] for some background on this