was exposed to military technology ideas. Lamarr met George Antheil, who had been at the forefront of experimental music in the 1920s, at a party in Hollywood. Antheil was one of the first people to work with the player piano as an instrument for composed music; his famous Ballet Mecanique was written for 12 player pianos, an airplane propeller, and a symphony. Antheil also opposed the Nazis, and it was in this context that Lamarr told Antheil about her idea for a secret communications system that could guide torpedoes to their target without being inter- cepted by the enemy, by sending messages between transmitter and receiver over multi- ple radio frequencies in a random pattern. The only problem was how to ensure that the transmitter and receiver would stay in synchronization as they moved through the fre- quencies. Lamarr thought Antheil could help solve the synchronization problem. Antheil did come up with a solution: Paper rolls perforated with a pseudorandom pattern would delineate the frequency path. Two rolls with the same pattern would be installed in the transmitter and receiver. If the two rolls were started at the same time, and one stayed at the launch point while the other was launched with the torpedo, the system would maintain the synchronization right on down to where the torpedo hit the ship. Interestingly, Lamarr and Antheil designed their system to use 88 frequen- cies-exactly the number of keys on a piano-just like the player piano rolls in Ballet Mecanique. Today, we call this technique Frequency Hopping Spread Spectrum (FHSS), and it is one of the ways in which spread spectrum uniquely encodes its conversations. Spread spectrum is characterized by not requiring any timing coordination, so clocking is not necessary. It offers great reliability because it is highly resistant to interference. Spread spectrum has greatly improved capacity over FDMA and TDMA; the spectral efficiency of spread spectrum, as standardized in IS-95, is 10 to 20 times greater than that of an analog cellular network. 