c(person(given = "Thomas", family = "Lumley", role =
        c("aut", "cre"), email = "tlumley@u.washington.edu"),
        person(given = "Ken", family = "Knoblauch", role = "ctb", email
        = "ken.knoblauch@inserm.fr"), person(given = "Scott", family =
        "Waichler", role = "ctb", email = "scott.waichler@pnl.gov"),
        person(given = "Achim", family = "Zeileis", role = "ctb", email
        = "Achim.Zeileis@R-project.org"))
Collapse red-green or green-blue distinctions to simulate
        the effects of different types of color-blindness.
Thomas Lumley [aut, cre], Ken Knoblauch [ctb], Scott Waichler
        [ctb], Achim Zeileis [ctb]