The Enigma Jewel // Locus of Enlightenment | Deserted Temple | Matzalantli, the Great Door // The Core

Cards

All permanents on the battlefield (
The Enigma Jewel // Locus of Enlightenment on the battlefield as
Locus of Enlightenment and
Matzalantli on the battlefield as The Core).
You have at least two permanent cards in your graveyard.

Activate The Core by tapping it, adding at least two mana of any color.
Activate
Deserted Temple's second ability by paying ({1} magic symbol) and tapping it, targeting itself.
Locus of Enlightenment triggers, copying
Deserted Temple's ability, targeting The Core.
Resolve both
Deserted Temple abilities, untapping it and The Core.
Repeat.

Once you have infinite mana, you may untap any other land except The Core instead.