Loose forms

I'm used to the idea of variation within a tight form, in particular established ones like sonnets. I prefer it when the looseness/tightness variation corresponds somehow to the content, or where expectation is exploited. Some other forms (e.g. those based on acrostics and anagrams) are less tolerant of imprecision.

"The Mizzy" by Paul Farley includes "The Sloth" which has a form whose details puzzle me.

• The indents (in characters) of the lines in stanza 1 are 0 4 0 2 2 4 6 2 4 6 0 1. In stanzas 2-11 the pattern is slightly different - 0 4 0 2 2 4 6 4 4 6 0 1.
• Lines 1 and 3 (same indent) only sometimes rhyme (down/sown, interference/chance, ants/haunts, appear/shy, life/limb, skull/fell, degrees/tree, growth/forgot, rain/trapped, earthed/fair, stand/planned).
• Line 4 has 2 syllables in all stanzas, line 5 has 8. The rest vary, I think (e.g. the first lines have 13, 14, 13, 14, 12, 12, 12, 13, 11, 14, 14 syllables, I think, and vary in their beat count).

Why make up a form just to break it? The expectation levels are so low that surprise is minimal. Maybe the title refers to the persona's laziness? Maybe it's like Islamic art, where the imperfections are deliberate? Or maybe it's poetry's equivalent of torn jeans.

Of course, the practice is nothing new. In Acumen 101, Fred Beake points out that in Tennyson's "Crossing the Bar",

• "the ten syllable lines ... occur in a different place in each stanza"
• "There are two ten syllable lines in stanza two and four and one in the other two"

"And yet somehow the very regular rhymed and the smooth wave like movement leave us with the illusion that this is a very regular poem"

My Relaxed Forms article has more info, looking at Larkin, etc