Mirzakhani obtained the asymptotic growth, when L→∞, of the number
of curves in the mapping class group orbit of some given simple curve and with
length at most L. Years later she extended this result from simple to
arbitrary curves. Here we give a short and relative low-tech argument showing
how to derive the general result from the one for simple curves.Comment: 9 pages; This replaces an earlier note, rather a research
announcement, which was not intended for publicatio