। ॥ ५३ ॥
In plain words
Say the superimposition runs both ways, each onto the other: then nothing whatever is left outside the two. And there is no projecting onto a void — emptiness gives nothing to project upon. So this is what to take hold of: advaita alone is true.
Close to the Sanskrit
If superimposition belongs to both, then — because of the absence of anything whatever distinct from those two — superimposition does not occur upon a void; therefore the truth of non-duality is to be grasped.