The Material Poem, an anthology of poetic artworks curated by UTS Masters student James Stuart, is available online: www.nongeneric.net
His introduction describes these poems as the products of writers "engaged with writing as a material rather than purely literary practice." Many of the poems are accompanied by author's notes explaining their motivations. Although I'm not looking at poetry (you'd have to go into a great deal of historical grounding to understand how the poem has evolved as a visual-verbal form, and I'm more interested in experimental visual devices in prose - traditionally the domain of pure language), this is a great example of how visual rhetorical devices affect the reading experience.
Quoting Charles Bernstein: " All text is visual when read", Stuart elaborates "engaging with language necessarily entails engagement with its particular materiality." It is this consideration of form, of materiality (or modality?) that is fascinating to me, as a designer. The 'design' of literature shifts from a paratextual zone (the cover, the typesetting grid) to an intertextual zone (the visual elements affect communication/meaning).
The process of reading poetry is recognised by the likes of Michel Riffaterre as being inherently different than the process prose: you read a poem once to identify the semiotic structure, and then again to understand the structure. You necessarily re-read poetry. This is what George Alexander describes in his statement: 'meaning in poetry often seems to float just out of reach, like lost paper sail boats'.
Wayzgoose Press describes the motivation to typeset one of their poems in differing faces and weights: "to encourage a slower and more deliberate reading than the average reader is accustomed to with today's universal emphasis on speed."