The Heart Does the Twist (image) Wyss Institute for Biologically Inspired Engineering at Harvard Share Print E-Mail Caption The heart circulates blood as if it were wringing a towel. The bottom twists in a counterclockwise direction while the top twists clockwise. On the right is the team's model of the heart, showing tube-like pneumatic artificial muscles that mimic the heart's striated muscle fibers. Credit Harvard Wyss Institute and Harvard School of Engineering and Applied Sciences Usage Restrictions Please, credit Harvard Wyss Institute and Harvard School of Engineering and Applied Sciences Share Print E-Mail 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.