According to Rabbi Levi quoting Rabbi Yohanan, the aron and the keruvim did not take up any space. In support of this teaching, the Gemara quotes a baraita that describes how the bodies of the keruvim took up no space, since the passage in Sefer Melakhim (I Melakhim 6:24) describes only the size of the wings, but not of the keruvim themselves.
The idea that is expressed by these teachings is that the aron and keruvim are not truly of this world – they are purely spiritual objects that cannot be measured by their physical existence; indeed, they do not take up any space in our physical world.
In describing how the keruvim stood, Rabbi Yohanan and Rabbi Elazar disagreed. One taught that the two keruvim faced one another, the other claimed that they faced the Temple. The Gemara points out that each of these positions has textual support – the pasuk in Shemot (25:20) says that they faced each other, while in Divrei HaYamim (II Divrei HaYamim 3:13) it says that they faced the Temple – and each of the amora’im explains the difference according to their approach. Either the keruvim faced somewhat sideways, or else their position changed. According to this approach, the keruvim represented the relationship between God and the Jewish People. When the Jews behaved properly and the relationship was good, the keruvim looked at each other, but when there were difficulties with the relationship, they looked away from one another. The idea that the keruvim are the forms of children, a popular theme in renditions of the aron, has its source in this Gemara, which quotes the great translator Onkelos as rendering the passage in Divrei HaYamim (II:3:10) as ma’aseh tza’atzu’im, which is understood by the rishonim as children.