The class is called histogram. To create a memeber of this class
h = histogram.new(xlabels, yvalues, grouplabels);where xlabels is the labels displayed on the horizontal axis used to identify each value. yvalues are the values to be compared. grouplabels is the labels used to identify each group of data. It can be left out if there's only one group.
hist = histogram.new(("a", "b", "c"), ((0.6, 0.25, 0.15), (0.7, 0.32, 0.27), ... (0.9, 0.2, 0.5)), ("Ocean", "Lake", "Pond")); hist.save("hist.eps");