Unity and repetition. A great example of Unity; with the repetition of the arc structure and reflection, place this image in a way that brings them all together. The spacing within the shadow on the wall also creates the sense of great proximity and mood.
World's most photographed spiral staircase at the Vatican Museums. Designed by Giuseppe Momo in The stairs are actually two separate helixes, one leading up and the other leading down, that twist together in a double helix formation.