Requires

Dual Strike must be in hand, or in exile. Fork must be in hand. You have a way to cast an additional instant or sorcery, or an opponent is casting one. Mana needed: , plus an additional if Dual Strike was not foretold, plus enough mana to cast the additional spell if needed

Steps

1. Cast any other instant and/or sorcery spell, or wait for an opponent to cast one.
2. Holding priority, cast Dual Strike by paying , copying the next instant or sorcery spell you cast with mana value four or less.
3. Cast Fork by paying , targeting the instant or sorcery spell cast in step 1.
4. Dual Strike triggers, copying Fork, with the copy targeting the original Fork.
5. Resolve the copy of Fork, copying Fork, with the copy targeting the original Fork.
6. Repeat step 5.

Results