(a) The track of a worm crawling on a paper-based device is illustrated in red (i). Velocity plot of a representative worm's centroid location is shown over 3 min in M9 buffer (ii). (b) The tracks of four worms swimming in four separate plastic-based devices are illustrated (i). Velocity plots of the four representative worms' centroid locations are shown over the course of 3 min in M9 buffer (ii).