  The conserved Kuramoto-Sivashinsky (CKS) equation, u_t = -(u+u_xx+u_x^2)_xx,
has recently been derived in the context of crystal growth, and it is also
strictly related to a similar equation appearing, e.g., in sand-ripple
dynamics. We show that this equation can be mapped into the motion of a system
of particles with attractive interactions, decaying as the inverse of their
distance. Particles represent vanishing regions of diverging curvature, joined
by arcs of a single parabola, and coalesce upon encounter. The coalescing
particles model is easier to simulate than the original CKS equation. The
growing interparticle distance \ell represents coarsening of the system, and we
are able to establish firmly the scaling \ell(t) \sim \sqrt{t}. We obtain its
probability distribution function, g(\ell), numerically, and study it
analytically within the hypothesis of uncorrelated intervals, finding an
overestimate at large distances. Finally, we introduce a method based on
coalescence waves which might be useful to gain better analytical insights into
the model.
