Requires

Retrofitter Foundry must be on the battlefield. Clock of Omens must be on the battlefield. Mana Vault must be on the battlefield. Zirda, the Dawnwaker must be on the battlefield. Mana needed:

Steps

1. Activate Retrofitter Foundry's second ability by paying and tapping it, creating a 1/1 Servo artifact creature token.
2. Activate Retrofitter Foundry's first ability by paying , untapping it.
3. Activate Clock of Omens by tapping Retrofitter Foundry and an untapped Servo token, untapping Mana Vault.
4. Activate Mana Vault by tapping it, adding .
5. Activate Retrofitter Foundry's first ability by paying , untapping it.
6. Activate Retrofitter Foundry's third ability by paying , tapping it, and sacrificing a tapped Servo token, creating a 1/1 Thopter artifact creature token with flying.
7. Activate Retrofitter Foundry's first ability by paying , untapping it.
8. Activate Clock of Omens by tapping Retrofitter Foundry and an untapped Thopter token, untapping Mana Vault.
9. Activate Mana Vault by tapping it, adding .
10. Activate Retrofitter Foundry's first ability by paying , untapping it.
11. Activate Retrofitter Foundry's fourth ability by tapping it and sacrificing a tapped Thopter token, creating a 4/4 Construct artifact creature token.
12. Activate Retrofitter Foundry's first ability by paying , untapping it.
13. Activate Clock of Omens by tapping Retrofitter Foundry and an untapped Construct token, untapping Mana Vault.
14. Activate Mana Vault by tapping it, adding .
15. Activate Retrofitter Foundry's first ability by paying , untapping it.
16. Repeat.

Results