Dan,
Another tweak !
If you want the 'legend' to look pretty you can resize it by adding,say,
'cex=0.6' into the legend code; try---
legend("topleft", #inset=-1,
legend = do.call("expression", L),
bg='white',
ncol = 2,
pch=c('','','',':',':',':'),
x.intersp = 0.4,
title="Yay! Thank You!",
cex=0.6
)
John