“They”
Although the title and content both indicate that the main characters are city planners, the use of the more mysteriously ambiguous “they” lends them an aura. These people are not just planners and builders of the necessities for urban living, they have a deeper agenda. They are symbols of the faceless bureaucracy capable of stimulating a seemingly bottomless well of conspiracy theories.
“the grace of mathematics”
The speaker uses the strange phrase “grace of mathematics” to describe the calculations necessary to create the perfect balance that makes everything come together in unison and keeps bridges from collapsing. Literally speaking, it is by the grace of these mathematical calculations that disaster is avoided, but the phrase is used ironically to lend it symbolism: the design is godless because the expectations that disaster can be avoided through the perfection of calculation ignores the reality of fate in an imperfectly designed universe.
Sea and Sky
In the face of this relentless building which seeks to correct the flaws of the past, the speaker the sea and sky capitulate to the calculations of man. God, intelligent design, Mother Nature: none of these concepts are mentioned directly but the reference to vast space between the sea and the sky is allusive symbolism meaning the same thing.
Dental Work
An extended metaphor occupies the second stanza in which the work being done by the city planners is compared to correcting the flaws associated with not taking care of one’s teeth. At its most essential level, however, this metaphor is not directed toward actual hygienic health, but cosmetics: it is about fixing teeth to make them look better. This metaphor become a symbol of one of the driving purposes of the planners: not to improve the condition of the city, but simply to make it look better.
“Anaesthesia, amnesia, hypnosis”
Part of the dental metaphor includes the numbing process by which surgical procedures can take place inside the mouth without causing pain. The speaker references this with a much more significantly symbolic intent. The numbing of the pain of new construction which make the city look better eventually results in the loss of memory of what things looked before. This systemic recurrence inevitably creates a kind of hypnotic effect that springs from expectations that future changes will likewise be painless. This metaphor becomes a symbol of bureaucratic control of the masses.
