Movie S1

Representative Cell-IQ real-time imaging of day 3–8 EBs formed from Bra-GFP/Rosa26-E2C mESCs. EBs were seeded at the density of 1.25×10⁵ cells mL^-1. Phase contrast images were acquired on an hourly basis. From around day 6, in some EBs, it appears that some cells started to migrate out, suggesting that they might be undergoing a gastrulation-like process (attached as a separate file).