Activate Viscera Seer by sacrificing Highspire Artisan.
When Highspire Artisan dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Highspire Artisan enters, its fabricate ability triggers, putting a +1/+1 counter on it.
Resolve the Viscera Seer ability.
Repeat.
This elegant loop relies on Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight to grant persist to your creatures once it transforms, setting up a clever dance of life and counters. You sacrifice Highspire Artisan to Viscera Seer, triggering its persist to return it with a -1/-1 counter; however, its fabricate ability immediately triggers upon re-entering to place a +1/+1 counter on it. Because state-based actions cancel out the opposing +1/+1 and -1/-1 counters simultaneously, the Artisan is left completely clean and ready to be sacrificed all over again.