Microspheres in a Magnetic Field (IMAGE) Max-Planck-Gesellschaft Caption Pumps teaming up and working together: In a magnetic field the microspheres (orange) form diamond shaped valves and a cog wheel. With skilful manipulation of a magnetic field, the wheel rolls through the cavity, and together with the valves pumps a fluid with colloid particles (blue) through the system. Credit Sabri Rahmouni/University of Stuttgart 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.