This brilliant loop relies on the constant, self-contained cycle of casting and bouncing your own automaton. As Ancestral Statue repeatedly enters the battlefield, Mana Echoes rewards your growing army of shared creature types by generating an escalating surplus of colorless mana with every iteration. Because Ancestral Statue's mandatory entry trigger forces you to return a nonland permanent—and you can simply choose the Statue itself—you have all the fuel you need to replay it endlessly, netting infinite mana and creature triggers so long as your typed presence on the board is large enough to sustain the casting cost.