ThinkCell type waterfall charts in R?

Hi Jim,

I looked through the plotrix documentation, and the waterfall plot comes
from the stackpoly function right?  I'm not sure if I can modify the
stackpoly to create the plot I want, since stackpoly is a line plot and
fills the area under with color.

I haven't played with all the options yet, but what I was looking for was
more similar to staircase.plot, but instead of horizontal bars, they would
be vertical columns.  Would you happen to know any packages or existing
plots that could be easily modified to do this?