Figure 2. Sequences of four midlines extracted from movies of worms moving in/on different media.

(a)–(c) Worm midlines have been displaced vertically, rotated, and aligned for clarity, with the head to the left and time increasing from top to bottom in quarter-period steps. The scale bar corresponds to approximately 0.1 mm. Estimated K values are (a) 35, (b) 35, and (c) 1.9. (d) Same midlines as above (a)–(c), still rotated, with the head to the left, but without removing the center of mass motion.