Time Sieve, Mycosynth Lattice, Bishop of Wings, and Xenograft

Prerequisites

• Time Sieve on the battlefield
• Mycosynth Lattice on the battlefield
• Bishop of Wings on the battlefield
• Xenograft on the battlefield
• You control at least five other creatures
• "Angel" chosen with Xenograft

Steps

1. Activate Time Sieve by tapping it and sacrificing five other creatures
2. When the creatures die as Angels due to Xenograft, Bishop of Wings' second ability triggers five times
3. Resolve the first trigger, causing you to create a 1/1 Spirit creature token
4. When the Spirit enters the battlefield as an Angel due to Xenograft, Bishop of Wings' first ability triggers, causing you to gain 4 life
5. Repeat from step 3 for each remaining trigger
6. Resolve the Time Sieve ability from step 1, causing you to take an extra turn after this one
7. Repeat each turn

Results

• Infinite turns
• Near-infinite lifegain