Activate Reito Lantern by paying 3, putting Threefold Thunderhulk on the bottom of your library from your graveyard.
Activate Grenzo by paying 2, putting Threefold Thunderhulk into your graveyard from the bottom of your library, and then putting it onto the battlefield.
When Threefold Thunderhulk enters the battlefield, it triggers, creating three 1/1 Gnome artifact creature tokens.
Activate Ashnod's Altar three times by sacrificing Threefold Thunderhulk and two Gnomes, adding six C.
Repeat.
This clever loop centers on Grenzo, Dungeon Warden, whose ability fishes creatures straight from the bottom of your library whenever their power matches Grenzo's stats. By using Ashnod's Altar, you sacrifice Threefold Thunderhulk alongside its own Gnome tokens to immediately generate the mana needed to keep the engine running, while also feeding Threefold Thunderhulk back to the graveyard. Finally, Reito Lantern closes the circuit by paying to tuck Threefold Thunderhulk right back onto the bottom of your library, perfectly positioned for Grenzo to pull it out all over again.