Retreat to Coralhelm + Scaled Herbalist + Dimir Aqueduct

Retreat to Coralhelm
Scaled Herbalist
Dimir Aqueduct

Requires
Dimir Aqueduct in hand. All other permanents on the battlefield. Scaled Herbalist does not have summoning sickness.
Steps
  1. Activate Scaled Herbalist 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 Scaled Herbalist
  5. Repeat
Results
Infinite landfall triggers.