Lands you control can tap to produce at least ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({R} magic symbol) .
Steps
Activate all mana-producing lands you control by tapping them, adding at least ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({R} magic symbol) .
If you have fewer than three experience counters, Mizzix of the Izmagnus triggers, causing you to get an experience counter.
Resolve Turnabout, untapping all lands you control.
Cast Mystic Retrieval by paying ({U} magic symbol) , returning Turnabout from your graveyard to your hand.
Cast Mystic Retrieval from your graveyard for its flashback cost by paying ({R} magic symbol) , returning Runic Repetition from your graveyard to your hand and exiling Mystic Retrieval.
Cast Runic Repetition by paying ({U} magic symbol) , returning Mystic Retrieval from exile to your hand.
Repeat.
If lands you control can tap to produce at least ({1} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({R} magic symbol) , this combo nets infinite mana.
Results
Infinite magecraft triggers.
Infinite mana permanents you control can produce.
Infinite storm count.
Infinite untap of permanents you control.
Instant/Sorcery with "Return Instant/Sorcery from GY to hand".