Basalt Monolith, Workshop Elders, and Heartstone

Prerequisites

• Basalt Monolith on the battlefield
• Workshop Elders on the battlefield
• Heartstone on the battlefield
• Basalt Monolith does not have summoning sickness

Steps

1. At the beginning of combat, Workshop Elders triggers, making Basalt Monolith a 0/0 artifact creature until end of turn and putting four +1/+1 counters on it
2. Activate Basalt Monolith's first ability by tapping it, adding
3. Activate Basalt Monolith's last ability by paying , untapping it
4. Repeat

Results

• Infinite colorless mana