When Dior first introduced its Dior VIII Grand Bal with a feather-adorned front rotor, the company’s designers likely had little inkling of how adaptable the winding rotor would prove to be. Since 2012, the number of decorative techniques applied to rotors has expanded to include mother-of-pearl, gemstones, and webs of silk thread; however, the company’s newest VIII Grand Bal Pièce Unique watches go several steps further in terms of extravagance. The 13 one-of-a-kind pieces (from approximately $140,000) are de…