Kaleea: That may have been _Catch As Catch Can_. I thought I owned it, but it seems not.

Some of the rounds were written so that when the parts were sung, meanings emerged that were not evident in unison. For example,

He would an alehouse keep must
Have three things in store:
A chamber with a featherbed, a
Chimney and a hey-nonny-nonny,....

Likewise, I see in _The Penguin Book of Rounds_

Here dwells a pretty maid whose name is Sis, you may come in and kiss.
Her whole, her whole, her whole, her whole estate is sev'nteen pence a year. Yet
you may kiss, you may kiss, you may kiss, you may kiss her if you come but near.

If the company sings "I've been working on the railroad" & "Old Black Joe" simultaneously, it sort of harmonizes, and "Dinah, won't you blow" is synchronized with "I'm coming".