stripchart.formula() works for me with your modification to stripchart.default().
Great!
But you don't need the 'bordered' pch for that.
Indeed, but this may improve lisibility: ##### n <- 500 x <- rnorm(n) y <- rnorm(n) fac1 <- rep(c("male", "female"), n) fac2 <- rep(c("blue", "red"), each = n/2) par(mfrow = c(1,2), lend = "butt", mar = c(5,4,1,1), oma = c(0,0,4,0)) plot(x, y, pch = ifelse(fac1 == "male", 15, 19), col = fac2, asp = 1) mbg <- rgb(0.9, 0.9, 0.9, 0.9) legend("topleft", inset = 0.02, c("male","female"), pch = c(15,19), bg = mbg) legend("bottomright", inset = 0.02, c("blue","red"), col = c("blue","red"), bg = mbg, lty = 1, lwd = 5) plot(x, y, pch = ifelse(fac1 == "male", 22, 21), bg = fac2, asp = 1) legend("topleft", inset = 0.02, c("male","female"), pch = c(22, 21), bg = mbg) legend("bottomright", inset = 0.02, c("blue","red"), col = c("blue","red"), bg = mbg, lty = 1, lwd = 5) mtext("Comparison of pch c(15, 19) versus c(22, 21)", outer = TRUE, cex = 1.5, line = 1) ###### Best, Jean -- Jean R. Lobry (lo...@biomserv.univ-lyon1.fr) Laboratoire BBE-CNRS-UMR-5558, Univ. C. Bernard - LYON I, 43 Bd 11/11/1918, F-69622 VILLEURBANNE CEDEX, FRANCE allo : +33 472 43 27 56 fax : +33 472 43 13 88 http://pbil.univ-lyon1.fr/members/lobry/ ______________________________________________ R-help@r-project.org 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.