Activate Goblin Bombardment by sacrificing Angel of Invention.
When Angel of Invention dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Angel of Invention enters, its fabricate ability triggers, putting a +1/+1 counter on it.
Resolve the Goblin Bombardment ability.
Repeat.
This loop harnesses Isilu, Carrier of Twilight's passive ability to grant persist to your nontoken creatures, allowing Angel of Invention to continuously cheat its own death when paired with Goblin Bombardment. Each time the Angel returns, the -1/+1 counter cancellation rule immediately wipes away its new -1/-1 counter by utilizing the +1/+1 counters placed on it via fabricate, keeping the cycle robust and preventing it from dying permanently. Meanwhile, Eirdu, Carrier of Dawn serves as the foundational enabler that gets your engine online in the first place, ensuring that your transformed dual-sided card supports both sides of the strategy.