Rings of Brighthearth, and Basalt Monolith

Prerequisites

• Rings of Brighthearth on the battlefield
• Basalt Monolith on the battlefield
• available

Steps

1. Activate Basalt Monolith's first ability by tapping it, adding
2. Activate Basalt Monolith's last ability by paying
3. Rings of Brighthearth triggers, causing you to pay to copy Basalt Monolith's last ability
4. Resolve the copy of Basalt Monolith's last ability, untapping it
5. Activate Basalt Monolith's first ability by tapping it, adding
6. Resolve the Basalt Monolith ability from step 2, untapping it
7. Repeat

Results

• Infinite colorless mana