Call to Glory in exile (Call to Glory exiled by Isochron Scepter).
Isochron Scepter and March of the Machines on the battlefield.
You control creatures that can tap to produce at least ({3} magic symbol) .
Steps
Activate creatures you control by tapping those, adding ({3} magic symbol) .
Activate Isochron Scepter by paying ({2} magic symbol) and tapping it, casting a copy of Call to Glory without paying its mana cost, untapping all creatures.