problems with mosaic plot

I'm pretty sure that I did everything right, but my R is just not drawing the
mosaicplot that I want, and there is also no error messege, looks like this
right now:

 mosaicplot(arthritis)
mosaicplot(~ sex + treatment + improved, data = arthritis, color = TRUE)

View this message in context: http://r.789695.n4.nabble.com/problems-with-mosaic-plot-tp3090128p3090128.html
Sent from the R help mailing list archive at Nabble.com.