at the same wall, in a simplified version of [@OlMe], where the clocks are assumed to have natural angular frequencies near each other but different. Here, we assume that the two clocks have the same angular frequency. When one clock receives the kick, the impact propagates in the wall slightly perturbing the second clock. The perturbation is assumed to be instantaneous since the time of travel of sound in the wall between the clocks is assumed very small compared to the period.

Consider two oscillators and index them by $i=1,2$. Each oscillator satisfies the differential equation $$\ddot{q}_{i}+\mu_{i}\text{ sign\ }\dot{q}_{i}+q_{i}=-\alpha_{i}\digamma\left(
q_{j}\right)  ,\text{ for }i,j=1,2\text{, }i\not =j\text{.}
\label{coupledandro}%$$ As in the *Andronov model*, the kinetic energy of each oscillator increases of the fixed amount $h_{i}$ when $q_{i}=-\mu_{i}$. The coupling term is the normalised force $-\alpha_{i}\digamma\left(  q_{j}\right)  $, where $\digamma$ is the interaction function and $\alpha_{i}$ a constant with acceleration dimension. Following [@OlMe], the effect of the interaction function $\digamma$ is considered to produce an increment $-\alpha$ in the velocity of each clock, leaving the position invariant when the other is struck by the energy kick. The reader finds the detailed treatment in [@OlMe]. Here we only recall some ideas from that article, 