Voltaic Key, Forsaken Monument, Rings of Brighthearth, and Arc Reactor

Prerequisites

• Voltaic Key on the battlefield
• Forsaken Monument on the battlefield
• Rings of Brighthearth on the battlefield
• Arc Reactor on the battlefield

Steps

1. Activate Arc Reactor by tapping it, adding
2. Forsaken Monument triggers, adding
3. Activate Voltaic Key by paying and tapping it, targeting itself
4. Rings of Brighthearth triggers, causing you to pay to copy Voltaic Key's ability, targeting Arc Reactor
5. Resolve both Voltaic Key abilities, untapping it and Arc Reactor
6. Repeat

Results

• Infinite colorless mana
• Infinite mana artifacts you control can produce
• Infinite untap of artifacts you control