Activate Tawnos's second ability by paying 1, tapping it and sacrificing two artifact tokens, exiling Little Bear from your graveyard and creating a token copy of it that is an artifact in addition to its other types.
When the Little Bear token enters, it triggers, untapping Tawnos.
Activate Tawnos's first ability by paying 2 and tapping it, creating a copy of the Little Bear token and causing you to mill two cards.
When the Little Bear token enters, it triggers, untapping Tawnos.
Activate Krark-Clan Ironworks by sacrificing a Little Bear token, adding CC.
Repeat from step 3.
This clever loop transforms Tawnos, Solemn Survivor into a tireless engine by using Krark-Clan Ironworks as both a mana source and a sacrificial outlet to fund the process. By paying Tawnos's second ability cost and exiling Little Bear from your graveyard, you create an artifact-creature token copy of Little Bear that immediately triggers its own entry ability to untap Tawnos. From there, Tawnos can use his first ability to rapidly duplicate that Little Bear token while milling your deck, generating a continuous loop of untaps, sacrifices, and re-creations.