The use of a strong constraint--that the poem must be readable horizontally as well as vertically--as well as the selection of the letter rather than the syllable as the word's quantum makes visual poetry more profoundly about the appearance of words on paper than sound- or time-based poetry which happens to be written on paper. Does it make any sense? Rather, we should ask, how does the poet dare be so open, flaying out his unconscious so shamelessly in this manner?