All about the description of The Valley of Ashes -
- Gutterall alliteration of "grotesque gardens" emphasises its ugliness (for lack of better word
- Description of "grey land", adjectival premodifier grey connoting a lack of personality - juxtaposes to the colourful description of the Buchanan house, connoting that in that era of America, money and decadence was needed to have substance and personality.
- Fitzgerald uses The Valley of Ashes to bring about the theme of death and decaying, potentially foreshadowing Myrtle's death there.
- Following on from that, the lexis of "ghastly" suggests something disgusting/shocking (which Myrtle's death is, the description of it is pretty horrible) and "crumbling" suggests the decay/death of something, again linking to her death and potentially Gatsby's too.
other random things:
- Valley of Ashes progresses the narrative by setting apart the differences between East/West Egg and showing socioeconomic differences between the Wilsons and Gatsby etc
- Eyes of T.J. Eckleburg highlight the theme of voyeurism: that Nick is always watching and commenting on the other characters, that Gatsby watches Daisy, etc.
- Tom and Myrtle's apartment as a microcosm of his world with Daisy, including the puppy which would represent Pammy.