Hopscotch, a children's sidewalk game, holds the abstract appearance of an arrow and in addition has a fixed direction from 1 to 10

Repetition solidifies the idea of childhood/youthfulness being something that can be reclaimed by following the way children play

Possible reference to pot holes or cracks where flowers are able to grow through

Returning to a measured journey rather than a quickly-paced one, or even a carefree pace of walking that is removed from any obligation to arrive at a set time

These lines seem to call for a return to a child-like nature opposed to "adulthood"

Lines possibly alluding to the "Twilight Years" of life, where the metaphorical path has ended but before death happens. These lines can also infer the ending of childhood, as the sidewalk ends at the curb which would normally be the boundary for a youths play area in the yard.

https://www.youtube.com/watch?v=LPwph2upVDo

Moonbird is a 1959 animated short in which two boys leave their house to try and capture the Moonbird. While this was likely not Silverstein's inspiration for this line, the short does come off as supernatural in tone as teh boys are consistently transparent or ghostly, alluding to a between state.

A crimson sun is generally associated with a sunset, another metaphor for an ending

https://youtu.be/Xxw8qEIj8-E Trepanning is an ancient form of surgery predating lobotomy. The brother punching holes in the skulls could serve as removing memories or feelings, or attempting to pacify or heal (and failing).

Jade was used it for medicinal purposes as well as for jewelry, ornaments, and religious artifacts, while turquoise has long been considered a stone that guarantees health, good fortune, and protection from evil.

The spots on a Peafowl's train symbolize the eyes of the gods in some cultures.

Sacrifice was viewed as a form of repayment to the gods for Ehecatl-Quetzalcóatl's crime of stealing bones from the underworld to create man.

Salt cedar is an invasive species which lowers the water table and deposits salt in the soil. This makes the land uninhabitable for other things which depend on the water and balanced mineral content of the soil.

The lack of capitalization both allows the piece to stand as a continuance of something prior, and thus unseen, but also allows the insertion of the title as its first line and beginning of the "narritive" of the piece.

Implies humanity is pig-like, e.g. lives in refuse, unclean, uncultured, obese, etc.

Double meaning of "bearing butter" as ball-bearing grease but also of having cooking butter. Central idea of surviving prior to the turn of the first stanza into industrialization.