Lands you control can tap to produce at least ({10} magic symbol) .
Steps
Activate all mana-producing lands you control by tapping them, adding at least ({10} magic symbol) .
Cast Turnabout by paying ({4} magic symbol) , untapping all lands you control.
Activate Urza by paying ({6} magic symbol) , creating a token copy of Archaeomancer that is a 1/1 Soldier in addition to its other types.
When the Archaeomancer token enters the battlefield, it triggers, returning Turnabout to your hand from your graveyard.
Repeat.
If lands you control can tap to proudce at least ({11} magic symbol) , this combo nets infinite mana, which can be used to activate Urza's ability infinitely and/or cast Turnabout choosing its other modes.
Results
Infinite colored mana.
Infinite creature copies of artifacts you control.