In this image, a Hele-Shaw cell formed from circular glass windows, oriented facing the camera, is illuminated by a white light source behind and to the right of the cell. Within the cell, the light is scattered by the ferrofluid particles in the high-field region near the poles of three magnets behind the cell. Blue LEDs along the rim of the cell provide background illumination.  

The second image shows two magnets with the light warping around them.