Overview of the evolution of the EFR (green rectangle in Fig. 2) at the lower atmosphere, in Hinode/SOT Ca II H (top row), G-band (middle row), and MDI (bottom row). The line in the last panel of the bottom row marks the area where the space-time slices of Fig. 8 were taken. Arrows indicate specific emergence events and features of interest (see main text). The magnetic field strength is scaled between ±40 G.