Helicity Experiment (VIDEO) University of Chicago This video is under embargo. Please login to access this video. Caption A leapfrogging helix produced by a carefully dyed hydrofoil. Credit William Irvine/University of Chicago Usage Restrictions With credit 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.