Prototype Portal + Clock of Omens + Battered Golem + Vault of Whispers

Prototype Portal

Clock of Omens

Battered Golem

Vault of Whispers

How it works

1. Activate Prototype Portal by paying 0, creating a token copy of Vault of Whispers.
2. When the Vault of Whispers token enters the battlefield, Battered Golem triggers, untapping itself.
3. Activate Clock of Omens by tapping Battered Golem and the Vault of Whispers token, untapping Prototype Portal.
4. Repeat.

This intricate setup hinges on feeding a lands-as-artifacts engine to achieve infinite activations. With Vault of Whispers safely exiled under Prototype Portal, you can churn out copies of the land for zero mana thanks to the X cost. Every time that Vault of Whispers token enters the battlefield, Battered Golem sees the new artifact and untaps itself automatically. From there, Clock of Omens steps in to tap the newly arrived Vault of Whispers token alongside Battered Golem, completely untapping Prototype Portal so the loop can begin anew.