דברי הימים ב, פרק ד׳, פסוק ד׳

The massive copper basin known as the Sea required a sturdy foundation to support its immense weight. This grand structure rested securely on a base made of twelve copper oxen.

The specific arrangement of these animals provides insight into the shape of the basin's base. Because the oxen were divided into groups aligned with the four directions of the compass, it is understood that the very bottom of the Sea was square. Three oxen were stationed at each of the four sides to hold up the heavy structure [רד״ק].

The faces of these twelve oxen were directed outward, looking toward the north, west, south, and east. It is carefully emphasized that the Sea sat on top of them, serving to clarify and reinforce the clear image that the heavy basin rested directly upon their backs [מצודת דוד, ביאור שטיינזלץ].

To complete this formation, the hindquarters of all the oxen pointed inward, tucked completely under the Sea so they remained hidden from view. Consequently, the back halves of the oxen facing north pointed directly toward the back halves of the oxen facing south, just as the hindquarters of the eastern oxen met those of the western ones in the center [רש״י, מצודת דוד, ביאור שטיינזלץ].