Activate Urza by paying 6, creating a token copy of Magic Pot that is a 1/1 Soldier and a 1/1 Thopter artifact creature token.
Activate Krark-Clan Ironworks twice by sacrificing the Magic Pot token and the Thopter, adding CCCC.
When the Magic Pot token dies, it triggers, creating a Treasure token and a 1/1 Thopter artifact creature token.
Activate Krark-Clan Ironworks by sacrificing the Treasure or the Thopter, adding CC.
Repeat.
This marvelous engine relies on Urza, Prince of Kroog to forge a token copy of Magic Pot for six mana, while Stridehangar Automaton steps in to quietly multiply your creation by adding an extra Thopter token to the mix whenever those artifacts enter. Once your board is populated, Krark-Clan Ironworks provides the necessary sacrifice outlet to dismantle your pieces for generous amounts of colorless mana. As the Magic Pot token perishes, its own death trigger springs to life to forge a Treasure token—which Stridehangar Automaton once again turns into a double bonus by yielding yet another Thopter alongside it—giving you all the resources needed to recast Urza's copying ability and loop infinitely.