[R] coloured letters in a text

[Fränzi Korner]

Hi

does somebody know how to plot single letters in a text in different
colours?

example 1: 
I would like to add the word "ABC" to a figure. Thereby each letter should
have a different colour.

text(x,y,"ABC", col=c(1,2,3))  # this does not work



example 2:
I would like to add the name of a parameter p with an index i to a figure.
The index i should be in red, whereas the rest of the text should be in
black.

text(x,y, expression(p[i]))


Looking forward to your answers!

Fränzi