Roxanne, Starfall Savant + Basalt Monolith + Echo Storm

Roxanne, Starfall Savant

Basalt Monolith

Echo Storm

How it works

1. Cast Echo Storm by paying 3, targeting Basalt Monolith.
2. Echo Storm triggers, copying it for each time you've cast your commander from the command zone this game, targeting any artifact.
3. Resolve all Echo Storms, creating a token copy of Basalt Monolith and any other artifact(s) as applicable.
4. Activate the token Basalt Monolith's first ability by tapping it, adding CCC.
5. Roxanne's second ability triggers, adding C.
6. Activate the token Basalt Monolith's second ability by paying 3, untapping it.
7. Repeat from step 4.