Tameshi, Reality Architect, Mind Over Matter, Ancient Den, and Darksteel Citadel

Prerequisites

• Tameshi, Reality Architect on the battlefield
• Mind Over Matter on the battlefield
• Ancient Den on the battlefield
• Darksteel Citadel in hand

Steps

1. Activate Ancient Den by tapping it, adding
2. Activate Mind over Matter by discarding Darksteel Citadel, untapping Ancient Den
3. Activate Ancient Den by tapping it, adding
4. Activate Tameshi by paying and returning Ancient Den from the battlefield to your hand, returning Darksteel Citadel from your graveyard to the battlefield
5. Activate Mind over Matter by discarding Ancient Den, untapping any applicable permanent
6. Activate Tameshi by paying and returning Darksteel Citadel from the battlefield to your hand, returning Ancient Den from your graveyard to the battlefield
7. Repeat

Results

• Infinite landfall triggers
• Infinite mana permanents you control can produce
• Infinite self-discard triggers
• Infinite untap of permanents you control