A friend of mine, Dan Chen, works on active microtubule systems and the results from his work have spawned a new project in the lab I work in. Microtubules are rigid rod-like filaments (think PVC pipes) that make up the “train tracks” for cargo transport inside the cell. Cargo is moved along the microtubules by motor proteins that more or less look like stick-figures that step along the tubes. If you attach two motors by their heads, instead of walking down the tubes, the double motor will make the two attached tubes slide past each other to make a chemically driven network that moves in a pretty mesmerizing way. Here is a video he captured using confocal microscopy! The microtubules are the bright rods that bundle together, and the motor proteins are too small to be seen.