Weaver of Harmony, Umbral Mantle, and Sanctum of Fruitful Harvest

Prerequisites

• Weaver of Harmony on the battlefield
• Umbral Mantle on the battlefield
• Sanctum of Fruitful Harvest on the battlefield
• available

Steps

1. At the beginning of your precombat main phase, Sanctum of Fruitful Harvest triggers
2. Holding priority, activate Weaver of Harmony by paying and tapping it, copying Sanctum of Fruitful Harvest's ability
3. Resolve the copy of Sanctum of Fruitful Harvest's ability, adding at least
4. Activate Weaver of Harmony by paying and untapping it, giving it +2/+2 until end of turn
5. Repeat from step 2

Results

• Infinite colored mana
• Infinitely large Weaver of Harmony until end of turn
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinitely large creature until end of turn