Among the rain
And lights
I saw the figure 5
In gold
On a red
Firetruck
After the scene is set, two lines later, the “I” enters the spotlight. 
 Here is where the title is incorporated: it turns out that “The Great Figure” is  the figure 5 . The firetruck’s movements and the number 5 seems to be all that Williams is inspecting in this whole poem–he does not even wonder about the fire that roused the firetruck. 
 
 The word ‘figure’ is ambiguous, meaning either a number or the human form. Both are relevant to this depiction of a city.
The Great Figure