I've been having trouble composing a response to this because my brain runs off in so many directions. So apologies if what follows is disjointed.
The writer of the kickoff essay above clearly knows the Sphere well, and I commend him or her for having the chutzpah to throw a challenge at us.
Though I haven't looked at my old books of critical theory to be sure, I think that concrete poetry hadn't even come to be included in textbooks when I was still studying. So I am ignorant; I confess my ignorance; I wait to be instructed. It's going to take more than one short essay for me to understand.
Because I don't yet understand, I'm more comfortable calling this visual art/conceptual art than poetry. My discomfort lies in the fact that any element of sound in the piece is an invention of the viewer/interpreter. It's a big leap from breves and macrons to "thump-thm." The symbols mean very different things in the poetries of different languages, and even within one type of poetry they mean different things. Syllable length in classical languages comes both from vowels and from piled-up consonants. Syllable stress in English comes from pitch and length and syntax, as well as the reader's expectation. So these macrons and breves are truly soundless by themselves. Compounding that is the fact that no natural language I know of (okay, that's a limited number) permits strings of unstressed, or of stressed, syllables as long as the strings in this piece. So I'm not only unable to decode sounds here; I'm even unable to imaging hearing them. I truly have to invent it all. The essay-writer invents a heartbeat, and I can buy that and even grant that it's a well-known metaphor for metrical effects. But it's an imagined element.
So an awful lot depends on the reader, and readers differ in their expectations of the aural and the visual in poems. We've seen this in our past discussions of going to, and giving, readings. I absolutely want to see the poem; some poets are terribly annoyed that anyone wants to read and not just to listen. For me the experience of the page is a major part of my experience of the poem and I'm likely to read without even subvocalizing at the first go. We know about such differences. So we already know that some of us can tolerate a page-only poem and some of us can't.
There's a continuum of types of poetry with a visual element, and I think this is at the extreme end. I have much less trouble with poems--and I'm happy to call them poems--in which sonics and visuals mix. Cummings of course did this long ago. A couple of right-now examples are Todd Boss (see his newest book,
Pitch) and
Marsha Pomerantz.
I have no good way to tie up all these tangles, but I'd like to keep thinking. I'd rather hear from others who know how to work with pieces like the one above than try to drive all such people away.