Basalt Monolith + Heartstone + March of the Machines

Basalt Monolith

Heartstone

March of the Machines

How it works

1. Activate Basalt Monolith's first ability by tapping it, adding CCC.
2. Activate Basalt Monolith's last ability by paying 2, untapping it.
3. Repeat.

By animating all noncreature artifacts into artifact creatures with March of the Machines, we cleverly bring Basalt Monolith within range of Heartstone's cost-reduction static ability. This means the {3} required to untap Basalt Monolith drops to {2}, creating a loop where tapping the artifact yields three colorless mana while the untap ability costs only two. Cycling through this process generates infinite colorless mana, turning an ordinary mana rock into a self-sustaining engine.