Cavalier of Dawn + Infinite Reflection + March of the Machines + Mox Amber

Cavalier of Dawn

Infinite Reflection

March of the Machines

Mox Amber

How it works

1. Cast Mox Amber by paying 0.
2. Mox Amber enters the battlefield as a copy of Cavalier of Dawn.
3. Copy of Cavalier of Dawn enter-the-battlefield ability triggers, destroying itself and creating you a 3/3 Golem token.
4. Copy of Cavalier of Dawn dies, triggering itself, returning Mox Amber from your graveyard to your hand.
5. Repeat.