[Groff] Graph in a man page

[Andre Majorel]

I'd like to include a simple diagram in a man page, something
like this :

                 _____       _____        _____
                |     |  A  |     |   C  |     |
                |  X  |---->|  Y  |----->|  Z  |
                |     |<----|     |<-----|     |
                |_____|  B  |_____|   D  |_____|

I suppose I could use tbl or switch to a fixed-spacing font and
use .nf. What would you recommend ?

It must work both in print and in a terminal and not depend on
Groff.

Thanks in advance.

-- 
André Majorel http://www.teaser.fr/~amajorel/