Three permanently magnetized liquid droplets floating in oil. As they spin in response to a rotating magnetic field, their activity wraps orange dye around themselves.

This artist’s drawing suggests what a floating solar-electricity and water-cleansing system might look like. Here the solar-cell panels are mounted atop a water clean-up system.

"Grid," by math artist Henry Segerman, explores mathematical concepts using projections. This 3-D printed sculpture is a patterned sphere. When light shines through the openings from above, the shadows form a square grid.

Individually, each of these disks can only expand and contract in place. But together, when loosely connected by magnets, they can complete a task like moving toward a light.