The game was born in 2012 while I was lounging by a pool during a vacation on the island of Rhodes (Greece). It was published under the name "Even or Odd" (Italian: "Pari o Dispari") in print form in the Focus Brain Trainer magazine (ed. Gruner+Jahr/Mondadori) in 2011 and 2012. Following the closure of the magazine, the game remained in a drawer for years until I retired and decided to propose it online.