Fred's Castel del Monte has a total of 56 facets (8 walls, with 48 sides on the 8 corner towers). He also died at age 56.
A man's his castle. (Birthday numbers... my poem's full of 'em.)
Each little section or canto of The Grassblade Light can be likened to an image, like a coin, cast in a mold. Not only are there 8 (in 7) parts : each part contains 28 (+ 1) sections; each section contains 28 lines (7 quatrain stanzas). (This is the template, anyway; there are some meaningful variations in the pattern). The central "+1" or 29th section of each part is designed as 4 x 4 quatrain stanzas (or 64 - 8x8 - lines).
28 x 2 = 56.
(One obvious pitfall of this kind of form is the temptation to fill in the pattern (with filler). Did I avoid that? Dunno... maybe.)
This is my goulden coinage of poetic value, Mandelstam's "gold coins of humanism". It's worth one penny, Penelope.