Ellipsis mode for zmacs?

[rsl@MAX-FLEISCHER.SF.Dialnet.ILA.COM (Richard Lamson)]

    Date: Tue, 25 Jun 91 12:30:47 -0600
    From: drstrip@cs.sandia.gov (David R. Strip)

    (sorry if this is a repost, seems to have gotten lost
    as far as I can tell)
    Is there some sort of ellipsis mode for zmacs? By that I mean
    a way of marking sections of buffer to be hidden (perhaps
    recursively). It would be great for outlining, code writing, etc.

I assume so, because Concordia uses it.  I don't know anything about how
you actually build buffers which can do this, though.