Patchwork Crawler, Trench Behemoth, and Llanowar Scout

Prerequisites

• Patchwork Crawler on the battlefield
• Trench Behemoth in exile
• Llanowar Scout in exile
• You have at least one land card in hand
• Patchwork Crawler does not have summoning sickness
• Trench Behemoth and Llanowar Scout exiled by Patchwork Crawler

Steps

1. Activate Patchwork Crawler using Llanowar Scout's ability by tapping it, putting a land from your hand onto the battlefield
2. If the land is mana-producing and enters the battlefield untapped, you may activate it by tapping it, adding at least
3. Activate Patchwork Crawler using Trench Behemoth's ability by returning the land from the battlefield to your hand, untapping Patchwork Crawler
4. Repeat

Results

• Infinite landfall triggers
• Infinite mana lands you control that enter the battlefield untapped can produce