This video is a summary of the findings reported in
the article "Chlamydomonas Swims with Two `Gears'
in a Eukaryotic Version of Run-and-Tumble Locomotion,"
by M. Polin, I. Tuval, K. Drescher, J.P. Gollub, and
R.E. Goldstein, Science 325, 487 (2009). (less info)