Retreat to Coralhelm | Dimir Aqueduct | Scaled Herbalist

Cards

Dimir Aqueduct in hand.
Retreat to Coralhelm and
Scaled Herbalist on the battlefield (
Scaled Herbalist without summoning sickness).

Activate
Scaled Herbalist by tapping it, putting
Dimir Aqueduct from your hand onto the battlefield.
When
Dimir Aqueduct enters the battlefield, it and
Retreat to Coralhelm trigger.
Resolve the
Dimir Aqueduct trigger, returning itself from the battlefield to your hand.
Resolve the
Retreat to Coralhelm trigger, untapping
Scaled Herbalist.
Repeat.