Prototype Portal, Gonti's Aether Heart, Thopter Assembly, and Ashnod's Altar

Prerequisites

• Prototype Portal on the battlefield
• Gonti's Aether Heart in exile
• Thopter Assembly on the battlefield
• Ashnod's Altar on the battlefield
• each turn available

Steps

1. At the beginning of your upkeep, Thopter Assembly triggers
2. Holding priority, activate Prototype Portal by paying and tapping it, creating a token copy of Gonti's Aether Heart
3. Gonti's Aether Heart enters the battlefield, causing you to get
4. Resolve the Thopter Assembly trigger, returning it from the battlefield to your hand and creating five 1/1 Thopter artifact creature tokens
5. The Thopters enter the battlefield, triggering Gonti's Aether Heart five times, causing you to get ten
6. Activate Ashnod's Altar five times by sacrificing the five Thopters, adding ten
7. Cast Thopter Assembly by paying
8. Thopter Assembly enter the battlefield, triggering Gonti's Aether Heart, causing you to get
9. Activate Gonti's Aether Heart by paying eight and exiling it, causing you to take an extra turn after this one
10. Repeat each turn

Results

• Infinite turns