To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie 6. Time lapse images of a representative embryo of perm-1 (RNAi) in 100 mM KCl solution. The embryo is identical to that shown in Fig. 5A. The elapsed time from the beginning of imaging is indicated in min: s. The extra-embryonic space and the local contour are crucial geometric constraints regulating cell arrangement Sungrim Seirin-Lee, Kazunori Yamamoto, and Akatsuki Kimura Development 2022. 149:None-None; doi: 10.1242/dev.200401 Download Original Video