Cast Walking Ballista by paying 1, causing it to enter the battlefield with a +1/+1 counter on it.
Activate Together Forever by paying 1, targeting Walking Ballista.
Activate Ashnod's Altar by sacrificing Walking Ballista, adding CC.
When Walking Ballista dies, Together Forever triggers, returning Walking Ballista from your graveyard to your hand.
Repeat.
This recursive loop turns Walking Ballista into an endlessly recastable engine by leveraging Together Forever to snatch it right back from the graveyard whenever it hits the bin. Ashnod's Altar acts as our mana-generating sacrifice outlet, providing the colorless mana needed to continuously fund both the sacrifice sacrifice-and-return cycle and the creature's casting cost. Meanwhile, Jhoira's Familiar quietly does heavy lifting in the background, reducing the cost of our historic artifact creature so the loop becomes self-sustaining and demands zero net mana to repeat indefinitely.