Luminous yellow lines overlap the black text. That alone would establish foreground/background relationships. But the contrast of yellow soft edges to the black hard edges further differentiates the two, increasing the sense of depth.
Andy Warhol - Cow II.12 | The Cow series was printed after Andy Warhol’s exhibition at the Leo Castelli Gallery, which inspired the creation of the wallpaper. This screenprint, Cow 12, is detailed with a yellow foreground against an electric blue background.