Retreat to Coralhelm + Llanowar Scout + Dimir Aqueduct

Retreat to Coralhelm
Llanowar Scout
Dimir Aqueduct

Requires
Dimir Aqueduct in hand. All other permanents on the battlefield. Llanowar Scout does not have summoning sickness.
Steps
  1. Activate Llanowar Scout by tapping it, putting Dimir Aqueduct from your hand onto the battlefield
  2. Dimir Aqueduct enters the battlefield, triggering itself and Retreat to Coralhelm
  3. Resolve the Dimir Aqueduct trigger, returning itself from the battlefield to your hand
  4. Resolve the Retreat to Coralhelm trigger, untapping Llanowar Scout
  5. Repeat
Results
Infinite landfall triggers.