Vulcan's forge - Velasquez

Apollo, on the left, enters Vulcan's forge, hard at work with his companions (basically Cyclops). He reveals to him the adultery of his wife, Venus, with Mars. Vulcan will forge the net that will ensnare the two lovers and make a spectacle of them, to the mockery of the Olympian gods.
Apollo describes a scene to Vulcan that we don't see: this scene of Venus' lovemaking is, however, the essential scene that gives meaning to what we see here. Apollo's haloed face stands out against the rectangle of the forge window, which opens onto the outside. This window links the scene we see to the one Apollo's speech asks us to render in our imagination. In contrast, Vulcan's sickly, counterfeit body leans towards the darkened back of the forge. It provides a link to the second circle, beyond the four protagonists positioned around the piece of red-hot iron: a young apprentice, witnessing the scene at the back of the workshop; to the right, another blacksmith hammering out a suit of armor; and above him, a jug resting on the edge of the mantelpiece. From these three points, the vague space points towards the scene itself.