Although he spends most of the time describing the animals running through the landscape, Cummings scatters a few very short, evocative phrases throughout the poem to paint the landscape. Here, the "level meadows" are described without any of the gushing descriptions of, say, the Romantic poets.
Softer be they than slippered sleep (16)
What? Since when does sleep wear slippers? In fact, since when does sleep have feet at all? Weirdly enough, the description of deer becomes a metaphor which personifies sleep. How's that for packing lots of figurative language into one short phrase?
four lean hounds crouched low and smiling (24)
The description of the hounds becomes something of a refrain in this poem, making them appear to be static—or at least unchanging—while the deer take on more and more language as the poem unfolds.