Shoes come in Threes

Nine West, Broadway.  Here's an odd fact.  Have you ever noticed how many shoe styles are displayed in threes ?  It seems counter-intuitive, but the human eye seeks out symmetry.  Three styles look better than two styles and better than four styles.   If you observe carefully, you will see the leading footwear retailers, especially in ladies footwear merchandise like this for key lines, although not for every line - that would be too monotonous for the eye.  Interesting isn't it, and there we thought shoes always came in pairs :)