Three lines, and almost nothing to hold onto, which is part of the point. The poem gives us a picture that doesn't quite settle: something "dutiful" and "tense" is "arrayed," or neatly lined up, inside "a nest of bats." Bats don't really build nests, so the phrase already feels slightly off, like a dream that gets a detail wrong.
The words pull in two directions. "Dutiful" and "arrayed" suggest order, discipline, things standing in rows. "Nest of bats" suggests darkness, crowding, and something a little unnerving. Put together, they create a mood of nervous obedience, as if someone or something is behaving properly while surrounded by unease.
"Tense" could even be read as grammar, a verb tense falling into line, though the poem doesn't say so. Judging by the title, "Thesis 7," it may be playing at being an argument and then giving us an image instead. There's no clear speaker or stated feeling here, just a tight, uneasy atmosphere you're left to interpret yourself.