This loop turns a simple sacrifice engine into an endless cycle of rebirth by leveraging the back side of Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, which grants your other nontoken creatures the persist ability. When you use Bloodflow Connoisseur to sacrifice Highspire Artisan, persist brings Highspire Artisan right back to the battlefield with a -1/-1 counter. Fortunately, Highspire Artisan's fabricate ability triggers upon re-entry, placing a +1/+1 counter on it that immediately neutralizes the -1/-1 counter through state-based actions. This leaves Highspire Artisan clean and ready to be sacrificed to Bloodflow Connoisseur all over again, generating an infinite number of creature sacrifices and enters-the-battlefield triggers.