Prototype Portal, Clock of Omens, Battered Golem, and Darksteel Citadel

Prerequisites

• Prototype Portal on the battlefield
• Clock of Omens on the battlefield
• Battered Golem on the battlefield
• Darksteel Citadel in exile

Steps

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

Results

• Infinite landfall triggers
• Infinite tapped Darksteel Citadel tokens