a, Schematics of bifurcating tissue development. b, Tissue area and lumen area as a function of culture time. c, Total cell number and T+ cell number as a function of culture time. d, Percentages of three types of tissues over time. e, Tissue thickness ratio plotted against tissue equivalent diameter. f, T+ cell intensity plotted against tissue thickness ratio. Color-coding in e and f denotes culture time. g, Diffusion maps of tissues. Color-coding denotes tissue thickness ratio, GATA3+ cell ratio and culture time as indicated. h, Bifurcating trajectory of amniotic-like and asymmetric tissues. i, GATA3+ cell ratio, NANOG+ cell ratio, T+ cell ratio and thickness ratio as a function of psuedotime of tissue development.