Thanks to all who helped me with this problem, especially Bill Venables and Gabor Grothendieck. I hope one day to learn more about the advanced features of the language used by Bill.
From a practical standpoint I think I will just avoid doing things like this in my teaching. It is hard enough just getting across the elementary ideas. Murray Jorgensen -- Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html Department of Statistics, University of Waikato, Hamilton, New Zealand Email: [EMAIL PROTECTED] Fax 7 838 4155 Phone +64 7 838 4773 wk Home +64 7 825 0441 Mobile 021 1395 862 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
