Alluvial plots use variable-width ribbons and stacked bar plots to
    represent multi-dimensional or repeated-measures data with categorical or
    ordinal variables; see Riehmann, Hanfler, and Froehlich (2005)
    <doi:10.1109/INFVIS.2005.1532152> and Rosvall and Bergstrom (2010)
    <doi:10.1371/journal.pone.0008694>.
    Alluvial plots are statistical graphics in the sense of Wilkinson (2006)
    <doi:10.1007/0-387-28695-0>; they share elements with Sankey diagrams and
    parallel sets plots but are uniquely determined from the data and a small
    set of parameters. This package extends Wickham's (2010)
    <doi:10.1198/jcgs.2009.07098> layered grammar of graphics to generate
    alluvial plots from tidy data.

The R package 'ggplot2' is a plotting system based on the
    grammar of graphics.  'GGally' extends 'ggplot2' by adding several
    functions to reduce the complexity of combining geometric objects with
    transformed data.  Some of these functions include a pairwise plot
    matrix, a two group pairwise plot matrix, a parallel coordinates plot,
    a survival plot, and several functions to plot networks.

Density, distribution function, quantile function and random generation for the Generalized Gamma proposed in Stacy, E. W. (1962) <doi:10.1214/aoms/1177704481>.

The grammar of graphics as implemented in the 'ggplot2'
    package has been successful in providing a powerful API for creating
    static visualisation. In order to extend the API for animated graphics
    this package provides a completely new set of grammar, fully
    compatible with 'ggplot2' for specifying transitions and animations in
    a flexible and extensible way.

Geoms for placing arrowheads at multiple points along a segment, not just at the end; position function to shift starts and ends of arrows to avoid exactly intersecting points.

A 'ggplot2' extension that adds specialised arrow geometry layers. 
    It offers more arrow options than the standard 'grid' arrows that 
    are built-in many line-based geom layers.