Schematic visualising the evolution of the molecular cloud filament, shown by the black curves, through the process of inflow (upper left panel), the monolithic formation of the first embedded cluster and termination of the inflow (upper right panel), the expansion of the first population due to gas expulsion and the ejection of the OB stars and resumption of gas inflow (middle panel), the monolithic formation of the second embedded cluster and termination of the inflow (lower left panel), the expansion of the second population due to gas expulsion and the ejection of its OB stars and resumption of gas inflow (lower right panel).