Three orientations of divisions can be seen in timelapse movies of cleavage stage Xenopus embryos. This movie covers the eight- to the 4096-cell stage, and is an example of the movies used for the timelapse analysis. It was also used to generate the still images shown in Fig. 3 and Fig. 4A. The movie shows three orientations of division: parallel divisions, which produce two daughter cells of approximately equal apical surface; oblique divisions, which produce one daughter cell with a large external (apical) surface and one with a small external surface; and perpendicular divisions, where the cells appear not to divide from the outside. Perpendicular divisions give rise to an outer cell and an inner cell that cannot be seen from the outside. The first of these occurs at the 32- to 64-cell stage. The embryo is viewed from the animal hemisphere with the future dorsal side to the top.