Sketch of the evolutionary stage of G31 within the F2C paradigm (Kumar et al. 2020). A hub is formed by the junction of filaments. The hub gravitational potential triggers and drives longitudinal flows, bringing additional matter and further enhancing the density. Hub fragmentation results in two star formation sites with different ages. Radiation pressure and ionization feedback escapes through the interfilamentary cavities by punching holes in the flattened hub.