

   AAdddd GGrriidd ttoo aa PPlloott

        grid(nx = 3, ny = 3, col = "lightgray", lty = "dotted")

   DDeessccrriippttiioonn::

        `grid' adds an `nx' by `ny' rectangular grid to an
        existing plot, using lines of type `lty' and color
        `col'.

   SSeeee AAllssoo::

        `plot', `lines', `points'.

   EExxaammpplleess::

        data(iris)
        plot(iris$Sepal.L, iris$Sepal.W, col = rep(1:3, rep(50, 3)),
             xlim = c(4, 8), ylim = c(2, 4.5))
        grid(4, 5, lty = "solid")

