Llanowar Scout + Arid Archway + Elven Raft-Steerer

Llanowar Scout

Arid Archway

Elven Raft-Steerer

How it works

1. Activate Llanowar Scout by tapping it, putting Arid Archway from your hand onto the battlefield.
2. When Arid Archway enters the battlefield, it and Elven Raft-Steerer trigger.
3. Resolve the Arid Archway trigger, returning itself from the battlefield to your hand.
4. Resolve the Elven Raft-Steerer trigger, untapping Llanowar Scout.
5. Repeat.