Rhythm Summation (IMAGE) Stanford University School of Engineering Caption The 19th century mathematician Joseph Fourier showed that two rhythms could be summed to produce a third rhythm. Researchers at Stanford have shown that this principle is behind the brain activity that produces arm movements. Credit Mark Churchland, Stanford School of Engineering Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.