Roxanne, Starfall Savant + Basalt Monolith + Mirrorworks

Roxanne, Starfall Savant

Basalt Monolith

Mirrorworks

How it works

1. Cast Basalt Monolith by paying 3.
2. When Basalt Monolith enters the battlefield, Mirrorworks triggers, causing you to pay 2 to create a token copy of Basalt Monolith.
3. Activate the token Basalt Monolith's first ability by tapping it, adding CCC.
4. Roxanne's second ability triggers, adding C.
5. Activate the token Basalt Monolith's second ability by paying 3, untapping it.
6. Repeat from step 3.

This clever loop relies on Mirrorworks to turn a single artifact into a self-sustaining engine the moment it enters the battlefield. By paying the extra mana, you secure a token copy of Basalt Monolith that can be repeatedly tapped for three colorless mana and untappped for three, creating a neutral mana exchange on its own. The true alchemy, however, comes from Roxanne, Starfall Savant, whose passive mana-doubling ability transforms that neutral exchange into a net positive by tacking on an extra mana every time an artifact token is tapped for mana. Together, these pieces turn a simple casting trigger into an endless fountain of colorless mana.