Rings of Brighthearth, Aphetto Alchemist, and Gilded Lotus

Prerequisites

• Rings of Brighthearth on the battlefield
• Aphetto Alchemist on the battlefield
• Gilded Lotus on the battlefield
• Aphetto Alchemist does not have summoning sickness

Steps

1. Activate Gilded Lotus by tapping it, adding three mana of any color
2. Activate Aphetto Alchemist by tapping it
3. Rings of Brighthearth triggers, allowing you to pay to copy Aphetto Alchemist's ability and choose a new target for the copy
4. Resolve both copies of Aphetto Alchemist's ability, untapping Aphetto Alchemist and Gilded Lotus
5. Repeat
6. Once you have infinite mana, you may untap any artifact or creature instead of Gilded Lotus in step 4

Results

• Infinite colored mana
• Infinite untap of artifacts and creatures