Arroyo or Ass-yoyo as it is nicknamed by its inhabitants is a small tribe built by the Vault Dweller dedicated to pussy. It was a small tribe with a population of 100 000 000, most of which were women. The town was built around a rock the Vault Dweller said looked like his dick. When he left the tribe in search of some new ladies no one really cared, in fact they were glad because the Vault Dweller was a doosh bag.