x and y variables with different
graphical properties for each distinct value of the grouping variable.panel.superpose(x, y, subscripts, groups, type="p", ...)
panel.superpose.2(x, y, subscripts, groups, type="p", ...)groups. The default
graphical parameters are obtained from superpose.symbol and
superpose.line using panel.xyplot for details of what the values
can be. The 2 functions panel.superpose and panel.superp
panel.xyplot. In particular, colour can be specified using 3
arguments (col, col.line, col.symbolpanel.xyplot