Ashnod's Altar, Graceful Reprieve, and Dualcaster Mage

Prerequisites

• Ashnod's Altar on the battlefield
• Graceful Reprieve in hand
• Dualcaster Mage in hand
• available

Steps

1. Cast Graceful Reprieve by paying its mana cost
2. Holding priority, cast Dualcaster Mage by paying its mana cost
3. When Dualcaster Mage enters, it triggers, copying Graceful Reprieve, with the copy targeting Dualcaster Mage
4. Resolve the copy of Graceful Reprieve
5. Holding priority, activate Ashnod's Altar by sacrificing Dualcaster Mage
6. When Dualcaster Mage dies, Graceful Reprieve triggers, returning Dualcaster Mage from your graveyard to the battlefield
7. Repeat from step 3

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite magecraft triggers