2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/126878A motion of point vortices with periodic boundary conditions is studied by using Weierstrass zeta functions. Scattering and recoupling of a vortex pair by a third vortex becomes remarkable when the vortex density is large. Clustering of vortices with various initial conditions is quantitated by the $L$ function used in point process theory in spatial ecology. It is shown that clustering persists if it is initially clustered like an infinite row or a checkered pattern.4 pages, 12 figures, to appear in JPSJFluid Dynamicstext