Looking up, we will see that three different stenciled patterns are found on the three different types of arches: across the nave, between pillars, and across the aisle. The designs are a chi-rho with alpha and omega, three interlocking rings with a cross, and a crown with a cross.
Chi and rho are letters of the Greek alphabet, and are the first two letters in the Greek word for Christ, "christos" (chi, rho, iota, sigma, tau, omicron, sigma). It has been used since time immemorial to represent the name of Christ in an abbreviated (or cryptic) form. The representation of "chi" appears as the Latin character "X." The representation of "rho" appears as the Latin character "P." On the stencil, these are accompanied with two other Greek letters, the alpha and omega. These are the first and last letters of the alphabet. Our lives should begin and end with Christ. In Him we find everything.
"I am the alpha and omega," says the Lord God, "the one who is, who was, and who is to come, the almighty." Revelation 1:8
Of course, the cross is a symbol of our salvation through Christ's curcifixion and resurrection.
The three interlocking rings is a symbol of the Trinity, three Persons in one God. A circle has neither a beginning nor an end, and so is a symbol of eternity. God is eternal.
The crown is a symbol of kingship. Pilate asked Christ if He were a king, to which He answered that His kingdom was not of this world. We celebrate Christ as our king, and, in His name, each of us has been baptized to be priest, prophet and king to each other. The Christian idea of kingship is service to all, as we were directed by Christ at the Last Supper.
