Requires

Rings of Brighthearth must be on the battlefield. Galvanic Key must be on the battlefield. Candelabra of Tawnos must be on the battlefield. High Tide must be in hand. You control at least two Islands. Mana needed:

Steps

1. Cast High Tide by paying , causing all Islands to add an additional when they are tapped for mana this turn.
2. Activate two Islands you control by tapping them, adding .
3. Activate Candelabra of Tawnos by paying and tapping it.
4. Rings of Brighthearth triggers, causing you to pay to copy Candelabra of Tawnos' ability.
5. Resolve the first Candelabra of Tawnos ability, untapping the two Islands.
6. Activate two Islands you control by tapping them, adding .
7. Resolve the second Candelabra of Tawnos ability, untapping the two Islands.
8. Activate Galvanic Key by paying and tapping it.
9. Rings of Brighthearth triggers, causing you to pay to copy Galvanic Key's ability.
10. Resolve both Galvanic Key abilities, untapping Galvanic Key and Candelabra of Tawnos.
11. Repeat from step 2.

Results