  Different numbers of self-gravitating particles (in different types of
periodic motion) are most likely to generate very different shapes of
gravitational waves, some of which, however, can be accidentally almost the
same. One such example is a binary and a three-body system for Lagrange's
solution. To track the evolution of these similar waveforms, we define a chirp
mass to the triple system. Thereby, we show that the quadrupole waveforms
cannot distinguish the sources. It is suggested that waveforms with higher
$\ell$-th multipoles will be important for classification of them (with a
conjecture of $\ell \leq N$ for N particles).
