3.6.2 Stacked Bar Charts

If several datapoints are supplied at a common $x$-coordinate to the boxes or wboxes plot styles, then the bars are stacked one above another into a stacked barchart. Consider the following datafile:

 
1 1
2 2
2 3
3 4

The second bar at $x=2$ would be placed on top of the first, spanning the range $2<y<5$, and having the same width as the first. If plot colours are being automatically selected from the palette, then a different palette colour is used to plot the upper bar.