We can see on the wall the shadow of the lettering on the window: “SAUSA”, carefully carved into an open space devoid of pictures and framed in the window pane shadow. Contextually, I’d say this is a reference comparing apartheid in South Africa with American racism, or at least Sal’s own line in the sand between honoring Sal’s own people while accepting the business of the black community without paying homage. In effect, Sal created a segregated pizza shop through his choice of who to honor and who to take money from. Also consider in this very frame that Buggin Out references “Nelson Mandela”. A very subtle visual reference indeed, but I would say it’s an implication of “South Africa USA”.