The lawnrings are empty. Blood skims the voids in your porous cranial plates, as if grazing the hollow of a threshed stem, or say, an abandoned cocoon.

The streets are empty. Wind skims the voids keeping neighbors apart, as if grazing the hollow of a cut reed, or say, a plundered mailbox.

lawnrings are presumably the closest thing trolls have to streets, and the setting of Karkat’s rant takes place in his own brain rather than in his neighbourhood so that the line about wind can be replaced with one about blood (though it probably has some implications regarding the interconnectedness of the characters’ homes and their inner worlds); but after using ‘threshed stem’ as a synonym for 'cut reed’, it feels particularly pregnant that a cocoon is compared to a mailbox? particularly because we know by now that a cocoon is a bed, so that’s not just their name for a mailbox. the very next page tells us trolls won’t even have a word for mailboxes because they don’t have mail full stop, so maybe those are just two parts to a joke, but trolls not having mail could be a part of this analogy too…