When Stonework Puma enters, Haru triggers, targeting Stonework Puma as it is a land due to Toph.
Activate Krark-Clan Ironworks by sacrificing Stonework Puma.
When Stonework Puma dies, Haru triggers, returning Stonework Puma from your graveyard to the battlefield tapped.
When Stonework Puma enters, Haru triggers, targeting Stonework Puma as it is a land due to Toph.
Repeat from step 3.
This ingenious loop turns your nontoken artifacts into lands thanks to Toph, the First Metalbender, transforming Stonework Puma—which enters as a land due to that continuous type-shifting effect—into a recursive engine. Haru, Hidden Talent bridges the gap by earthbending the Puma whenever it enters or leaves the graveyard, immediately pulling it right back to the battlefield when sacrificed. By feeding this animated land straight into Krark-Clan Ironworks, you turn the physical recycling of the Puma into a generous surplus of colorless mana while looping all your artifact and creature triggers indefinitely.