This clever loop relies on the interaction between Isilu, Carrier of Twilight's static ability—which grants persist to your nontoken creatures—and Vizier of Remedies, whose replacement effect prevents those persist counters from sticking entirely. By sacrificing Linvala, Shield of Sea Gate to trigger its own protection ability, you send her to the graveyard, only for persist to bring her right back with a clean slate. Because Eirdu, Carrier of Dawn is just the front face of that same transforming double-faced card (and contributes convoke to your spells along the way), this engine effortlessly churns out an infinite number of sacrifice, death, and entry-the-battlefield triggers.