Wow, you art-types are good at spotting that stuff. .
For me, it has nothing to do with being an "art-tpye", for I always struggled with art appreciation classes. Reading the mediations of others has helped me to appreciate Icons, many of which contain strong albeit subtle geometric elements.
In the Rublev Icon, often called "The Old Testament Trinity" there is an apparent conversation between the divine beings. A small chalice on the table, containing the head of the sacrificed calf given by Abraham to the angelic visitor is thus the chalice within the chalice.
One of the messages of this Icon is that God through the Sacrament of the Eucharist is inviting us "to table"; that is, to become a part of the Divine conversation. This invitation is possible only through the sacrifice of the Son, the Lamb of God who takes away the sins of the world.