Adaptive Training Post + Return the Favor

Prerequisites

You have an instant or sorcery card in hand with enough mana to cast it. You have enough mana to cast Return the Favor

Steps

1. Cast the additional instant or sorcery by paying its mana cost.
2. If Adaptive Training Post had two charge counters on it, it triggers, putting a charge counter on it.
3. Holding priority, activate Adaptive Training Post by removing three charge counters from it, copying the next instant or sorcery spell you cast this turn.
4. Cast Return the Favor by paying its mana cost, targeting the spell cast in step 1.
5. Adaptive Training Post triggers, copying Return the Favor, with the copy targeting the original Return the Favor.
6. Resolve the copy of Return the Favor, copying the original Return the Favor, with the copy targeting the original Return the Favor.
7. Repeat step 5.