cascade

a small waterfall or series of small waterfalls

a succession of stages or operations or processes or units; "progressing in severity as though a cascade of genetic damage was occurring"; "separation of isotopes by a cascade of processes"

a sudden downpour (as of tears or sparks etc) likened to a rain shower; "a little shower of rose petals"; "a sudden cascade of sparks"

rush down in big quantities, like a cascade

arrange (open windows) on a computer desktop so that they overlap each other, with the title bars visible