R graphs: Creating Tufte's horizontal bar lines

Question

How can we replicate Tufte\'s implicit horizontal lines in R?

For example, the following

Answer 1

There's also a pretty easy base R solution for this:

tmp <- table(msleep$order)
barplot(tmp, col='black', las=3)
abline(h=seq(5, max(tmp), by=5), col='white', lwd=2)