Compare Decoud's "Like a wall" in the darkness of the Gulf
and Charles Gould's wall with letters of fire upon it.
Wall imagery in Nostromo corresponds to a character recognizing the "walls"
of subjectivity that isolate one soul from another. With Decoud in the Gulf it
concerned hiding: he enjoyed being shielded from the sight of others. With Charles
Gould it concerned manipulating: it came in the context of him tailoring a letter
to flatter Holroyd's subjective vanity. Here, Nostromo has returned to the prototypical
spot of his old fidelity, nursing a secret revolt that the other's subjective
mindset cannot see or understand. The description of the running spider implies
that Nostromo's eyes are actually roving around the wall, suggesting a sense of
being trapped by this isolation and dishonesty.