When Oboro, Palace in the Clouds enters the battlefield, Sapling Nursery and Kodama of the East Tree trigger.
In response, activate Oboro's first ability by tapping it, adding .
Activate Oboro's last ability by paying 1, returning it from the battlefield to your hand.
Resolve the Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Sapling Nursery trigger, creating a token.
When the token enters the battlefield, Kodama of the East Tree triggers, putting Oboro from your hand onto the battlefield.
When Oboro, Palace in the Clouds enters the battlefield, Sapling Nursery triggers.
Repeat from step 3.
This ingenious loop uses Kodama of the East Tree as a bridge between your lands and your token generators, turning a simple landfall trigger into a self-sustaining engine. When Oboro, Palace in the Clouds enters the battlefield, it sets off both Sapling Nursery and Kodama of the East Tree, allowing you to float blue mana and bounce Oboro back to your hand before those triggers even resolve. The resulting Sapling Nursery landfall trigger creates a 3/4 green Treefolk creature token, which in turn triggers Kodama of the East Tree to seamlessly drop Oboro right back onto the battlefield from your hand. By repeating this process, you get an endless parade of Treefolk, entering the battlefield alongside limitless landfall triggers.