How to show the distribution of several data set together

# simulate data
x1 <- rnorm(1000, 0.4, 0.8)
x2 <- rnorm(1000, 0.0, 1.0)
x3 <- rnorm(1000, -1.0, 1.0)

# density plots
plot(density(x1), xlim=range( c(x1, x2, x3) ), main="", xlab="" )
lines(density(x2), col=2)
lines(density(x3), col=3)

# rug plots for displaying actual data points
rug(x1, col=1, ticksize=0.01, line=2.5)
rug(x2, col=2, ticksize=0.01, line=3.0)
rug(x3, col=3, ticksize=0.01, line=3.5)



#========================================================
# or use stacking box plot
x1 <- rnorm(1000, 0.4, 0.8)
x2 <- rnorm(1000, 0.0, 1.0)
x3 <- rnorm(1000, -1.0, 1.0)
all <- c(x1, x2, x3);
hist(x1, breaks=seq(min(all), max(all)+0.999, by=0.1),
xlim = c(min(all), max(all+0.01)), ylim=c(0, 55),
main = "hist", xlab = "distribution", ylab= "", col=1);
box();

par(new=T);
hist(x2, breaks=seq(min(all), max(all)+0.999, by=0.1),
xlim = c(min(all), max(all+0.01)), ylim=c(0, 55),
main = "", xlab = "", ylab= "", col=2);
box();

par(new=T);
hist(x3, breaks=seq(min(all), max(all)+0.999, by=0.1),
xlim = c(min(all), max(all+0.01)), ylim=c(0, 55),
main = "", xlab = "", ylab= "", col=3);
box();