When George returned, he wanted to do something to help the war effort. He tried enlisting in the army, but he was too old. He later met Hedy at a party in Hollywood and they became friends. The two discovered that they shared a common feeling of hatred toward Hitler and the Nazi Party. It was for this reason that Hedy approached George with the synchronization problem of her Secret Communications System. George knew a lot about synchronization from his work making music by keeping machines synchronized. George came up with the idea of using player piano rolls to solve this problem. A player piano roll would control the frequency hopping of the transmitter. Likewise, an exact duplicate of that player piano roll, started at the same time, would control the frequency hopping of the receiver, thus the two would be synchronized. This is analogous to playing the same song on two player pianos at the same time. The player piano rolls that they used controlled hopping between 88 possible frequencies just like the piano has 88 keys. Each message was sent using unique random frequency patterns, thereby making it extremely difficult for the enemy to figure out the pattern.