Zirda, the Dawnwaker + Bigger on the Inside + Retrofitter Foundry

Zirda, the Dawnwaker

Bigger on the Inside

Retrofitter Foundry

How it works

1. Activate Retrofitter Foundry by tapping it, adding two mana of any color and causing the next spell you cast this turn to have cascade.
2. Activate Retrofitter Foundry's first ability by paying 1, untapping it.
3. Repeat.
4. Once you have infinite mana, you may activate Retrofitter Foundry's other abilities.

This elegant loop comes together when Bigger on the Inside enchants Retrofitter Foundry, granting the artifact the powerful ability to tap for two mana of any color while giving your next spell cascade. Because Zirda, the Dawnwaker sits in your command zone or deck as a companion, its passive cost-reduction ability alters the math entirely: Retrofitter Foundry's untap ability normally costs {3}, but Zirda reduces it down to {1}. Tapping the enchanted Foundry for two mana and spending just one of those mana to untap it creates a self-sustaining engine that yields infinite colored mana, infinite cascade triggers, and eventually an army of infinite Servo, Thopter, and Construct tokens.