Creeley, isoverbal prosody, quatrain stanzas

I've been reading a lot of Robert Creeley lately. Here's a poem I like:

When i think

When I think of where I've come from
or even try to measure as any kind of
distance those places, all the various
people, and all the ways in which I re-
member them, so that even the skin I
touched or was myself fact of, inside,
could see through like a hole in the wall
or listen to, it must have been, to what
was going on in there, even if I was still
too dumb to know anything-When I think
of the miles and miles of roads, of meals,
of telephone wires even, or even of water
poured out in endless streams down streaks
of black sky or the dirt roads washed clean,
or myriad, salty tears and suddenly it's spring
again, or it was-Even when I think again of
all those I treated so poorly, names, places,
their waiting uselessly for me in the rain and
I never came, was never really there at all,
was moving so confusedly, so fast, so driven
like a car along some empty highway passing,
passing other cars-When I try to think of
things, of what's happened, of what a life is
and was, my life, when I wonder what it meant,
the sad days passing, the continuing, echoing deaths,
all the painful, belligerent news, and the dog still
waiting to be fed, the closeness of you sleeping, voices,
presences, of children, of our own grown children,
the shining, bright sun, the smell of the air just now,
each physical moment, passing, passing, it's what
it always is or ever was, just then, just there.

I have read that Creeley wrote in variable isoverbal prosody. But I don't know what that means. Here's another poem I like:

an obscene poem

The girl in the bikini, my
wife, the lady-she sits on
the rocks, crouched
behind a jagged encumbrance.

Calamares, canalones-
the fisherman's daughter.
At night a dull movement
on the sands

and lightly at low tide
on the rocks
bland, undulant
she returns.

I also read that his stanzas are quatrains, but I don't what this means either. Here's a poem Creeley himself likes:

the charm

My children are, to me,
what is uncommon: they are dumb
and speak with signs. Their hands

are nervous, and fit more for
hysteria, than goodwill or long
winterside conversation.

Where fire is, they are quieter
and sit, comforted. They were born
by their mother in hopelessness.

But in them I had been, at first,
tongue. If they speak,
I have myself, and love them.

'When I first began writing,' Creeley said, 'I was very didactic and very involved with 'doing it right'. There was so much then to qualify what was acceptably a poem, and what was not. For example, there is a lovely story told me by John Frederick Nims about a fried of his reading somewhere in the Midwest. At the end someone in the audience asked if questions were permitted, and being told they were, said that he had one concerning the next to last poem read-to wit, 'Was that a real poem or did you just make it up yourself?'

I have a number of questions myself: what does 'isoverbal prosody' mean? And what is a 'quatrain stanza'? And what does Creeley mean when he says he was 'very didactic' and in what way was he concerned with 'doing it right'?

Robert Creeley died in Texas on March 30, 2005 of complications from pneumonia.