  We are concerned with the dynamics of one fold symmetric patches for the
two-dimensional aggregation equation associated to the Newtonian potential. We
reformulate a suitable graph model and prove a local well-posedness result in
sub-critical and critical spaces. The global existence is obtained only for
small initial data using a weak damping property hidden in the velocity terms.
This allows to analyze the concentration phenomenon of the aggregation patches
near the blow up time. In particular, we prove that the patch collapses to a
collection of disjoint segments and we provide a description of the singular
measure through a careful study of the asymptotic behavior of the graph.
