Requires

Lumra, Bellow of the Woods must be in the graveyard. Port of Karfell must be on the battlefield. Tiller Engine must be on the battlefield. Squandered Resources must be on the battlefield. You can produce at least between sacrificing lands excluding Port of Karfell to Squandered Resources and/or by tapping those lands for mana.

Steps

1. If desired, activate any number of other mana-producing lands you control by tapping them, adding at least for each land tapped this way.
2. Activate Squandered Resources by sacrificing a mana-producing land other than Port of Karfell, adding or if possible, or any other type of mana otherwise.
3. Repeat step 2 until you control no other mana-producing lands except Port of Karfell.
4. Activate Port of Karfell's second ability by paying , tapping and sacrificing it, causing you to mill four cards and return Lumra from your graveyard to the battlefield tapped.
5. Lumra enters the battlefield and dies as a state-based action due to having 0 toughness.
6. Lumra's enter-the-battlefield ability triggers, causing you to mill four cards and return all land cards from your graveyard to the battlefield tapped.
7. When the lands enter the battlefield, Tiller Engine triggers that many times, untapping the lands.
8. Repeat.

Results