Time Sieve, Mycosynth Lattice, Rionya, Fire Dancer, and Phylath, World Sculptor

Prerequisites

• Time Sieve on the battlefield
• Mycosynth Lattice on the battlefield
• Rionya, Fire Dancer on the battlefield
• Phylath, World Sculptor on the battlefield
• You control at least five basic lands

Steps

1. At the beginning of your combat phase, Rionya triggers, creating at least one token copy of Phylath with haste
2. Put the Phylath token into your graveyard due to the legend rule
3. The Phylath token enters-the-battlefield ability triggers, creating at least five 0/1 Plant creature tokens
4. Activate Time Sieve by tapping it and sacrificing the Plant tokens, causing you to take an extra turn after this one
5. Repeat each turn

Results

• Infinite turns