the same, with the same conclusions.

Model for three pendulum clocks placed in the three vertices of an equilateral triangle
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Hypotheses
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We consider three pendulum clocks suspended at the same wall, placed in the three vertices of an equilateral triangle, say the vertices are $A$, $B$, and $C$ and $B$ are the extreme points of the basis of the triangles.

\[ptb\]

[triangle.eps]{}

This geometric setting is purely conceptual. Any set of three dynamical systems receiving symmetric impacts from the other two will have the same type of response of the clocks depicted in the three vertices of an equilateral triangle.

Call the clocks placed in the three vertices $A$, $B$ and $C$, respectively, $O_{1}$, $O_{2}$ and $O_{3}$. When the clock $A$ receives the kick from the escape mechanism, the impact propagates in the wall slightly perturbing the other two clocks. As in [@OlMe], 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. As for the two clocks model discussed in [@OlMe], we make the following assumptions, now formulated for three clocks.

1.  The system has [dry friction ]{}[@And].

2.  