Tracking results (VIDEO) Optica This video is under embargo. Please login to access this video. Caption The simulated movie shows the coordinates calculated while tracking a metal sphere moving down a curved spiral wire. Credit Zihan Geng, Tsinghua University Usage Restrictions None License Original 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.