When I looked at this later, just to confirm that cross figure, I realized that there are actually three:
The three crosses bring the crucifixion to mind: "Then two robbers were crucified with him, one on the right and one on the left" (Matthew 27:38).
Because there are three crosses, there's also some resonance with the Trinity, especially since the cross figures overlap. It's sort of a visualization of the "one God in three persons and three persons in one God" that the Athanasian Creed mentions. The constituent notes of the crosses are significant in that they're the three notes that make up a C major triad: C, E, and G; there's also a C an octave higher than the first (I think it's also salient that it's in C major - a key with no accidentals). So there are three crosses, the three figures of the Trinity, and the three notes of the triad.
