Irenicus's Vile Duplication and Boros Garrison in hand.
({3} magic symbol) ({U} magic symbol) available.
Steps
Cast Irenicus's Vile Duplication by paying ({3} magic symbol) ({U} magic symbol) , creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Boros Garrison.
Both Kodama of the East Trees and Boros Garrison trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Boros Garrison trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Boros Garrison from your hand onto the battlefield.
The token Kodama of the East Tree and Boros Garrison trigger.
Resolve the Boros Garrison trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Boros Garrison from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Boros Garrison trigger.