Adaptive Training Post + Insidious Will

Prerequisites

You have an instant or sorcery card in hand with enough mana to cast it. You have enough mana to cast Insidious Will

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 Insidious Will by paying its mana cost, targeting the spell cast in step 1.
5. Adaptive Training Post triggers, copying Insidious Will, with the copy targeting the original Insidious Will.
6. Resolve the copy of Insidious Will, copying the original Insidious Will, with the copy targeting the original Insidious Will.
7. Repeat step 5.