the color gray in the book symbolizes in between. the color gray is in between the color white and black. the valley of ashes,new york city black . valley of ashes, east egg and west egg white
seems like city is bad but really is other way around. east egg and west egg has adultary .. nick in beginings says city is bad everyones lonely..then says in the end that its good and full of light.
he saw how bad eggs are.