panel.doublerug {DAMisc}  R Documentation 
This panel function is defined to plot two rugs, one on top of the other in a multipanel lattice display.
panel.doublerug(
xa = NULL,
xb = NULL,
regular = TRUE,
start = if (regular) 0 else 0.97,
end = if (regular) 0.03 else 1,
x.units = rep("npc", 2),
lty = 1,
lwd = 1
)
xa, xb 
Numeric vectors to be plotted. 
regular 
Logical flag indicating whether rug is to be drawn on the usual side (bottom/left) as opposed to the other side (top/right). 
start, end 
Start and end points for the rug ticks on the yaxis. 
x.units 
Character vectors, replicated to be of length two. Specifies
the (grid) units associated with start and end above. x.units are for the
rug on the xaxis and yaxis respectively (and thus are associated with
start and end values on the y and x scales respectively). See

lty, lwd 
Line type and width arguments (see 
Dave Armstrong