Orvar, the All-Form + Clockspinning + Harmonic Prodigy
Other: Infinite copies of permanents you control, Infinite creature tokens, Infinite ETB, Infinite landfall triggers, Infinitely large creatures you control until end of turn, Infinite magecraft triggers, Infinite mana permanents you control can produce, Infinite storm count
Cast Clockspinning with buyback by paying {3}{U}, targeting Harmonic Prodigy.
Orvar triggers twice and Harmonic Prodigy triggers once.
Resolve the Harmonic Prodigy trigger, giving it +1/+1 until end of turn.
Resolve the Orvar triggers, creating two token copies of Harmonic Prodigy.
Resolve Clockspinning, returning it to your hand.
Cast Clockspinning with buyback by paying {3}{U}, targeting Harmonic Prodigy.
Orvar triggers four times, and each Harmoic Prodigy triggers three times.
Resolve all Harmonic Prodigy triggers, giving each Harmonic Prodigy +3/+3 until end of turn.
Resolve all Orvar triggers, creating four token copies of Harmonic Prodigy.
Resolve Clockspinning, returning it to your hand.
Cast Clockspinning with buyback by paying {3}{U}, targeting any nonlegendary permanent you control that enters the battlefield untapped and that can tap to produce at least {U}.
Orvar triggers eight times, and each Harmonic Prodigy triggers seven times.
Resolve all Harmonic Prodigy triggers, giving each Harmonic Prodigy +7/+7 until end of turn.
Resolve all Orvar triggers, creating eight copies of the mana-producing permanent.
Resolve Clockspinning, returning it to your hand.
Activate four of the copies of the mana-producing permanent by tapping them, adding at least {U}{U}{U}{U}.
Repeat from step 11.
Cards: Orvar, the All-Form, Clockspinning, Harmonic Prodigy