Cast the Dwarf with mana value 1 that's in your hand by paying its mana cost.
When the Dwarf enters, Cloudstone Curio and Thorin trigger.
Resolve the Cloudstone Curio trigger, returning the other Dwarf with mana value 1 from the battlefield to your hand.
Resolve the Thorin trigger, creating a Treasure token.
Activate the Treasure by tapping and sacrificing it, adding .
Repeat.
This delightful loop transforms the humble Dwarven Trader and Dwarven Grunt into an endless engine of productivity, fueled entirely by the presence of Cloudstone Curio and Thorin, King of Durin's Folk. As you repeatedly cast and bounce your low-cost Dwarves, Cloudstone Curio manages the battlefield hand-off by returning your other Dwarf to your hand whenever a nonartifact permanent enters. Meanwhile, Thorin, King of Durin's Folk turns every single entry into a shiny new Treasure token whose sacrifice easily pays the mana needed to keep casting your tiny companions.