Fig. 6. A broad shear zone develops at the equator of BDM-treated activated eggs. The frame from a side-view time-lapse sequence spanning a 20 minute period at the beginning of torsion (see Movie S3 in the supplementary material). Motion of individual pigment granules (marks 1-6) traced via time-lapse is indicated by colored tracks. The colored bar indicates a 20 minute time interval (blue: start of tracking; red: +20 minutes).