Burst of Energy in exile (exiled by Isochron Scepter).
Isochron Scepter and Swarm Intelligence on the battlefield.
You control a permanent that can tap to produce at least ({3} magic symbol) .
Steps
Activate a permanent you control by tapping it, adding at least ({3} magic symbol) .
Activate Isochron Scepter by paying ({2} magic symbol) and tapping it, casting a copy of Burst of Energy without paying its mana cost, targeting Isochron Scepter.
Swarm Intelligence triggers, creating a copy of Burst of Energy, targeting the permanent that can tap to produce at least ({3} magic symbol) .
Resolve both Burst of Energy copies, untapping Isochron Scepter and the permanent.