Basalt Monolith, Heartstone, and Toymaker

Prerequisites

• Basalt Monolith on the battlefield
• Heartstone on the battlefield
• Toymaker on the battlefield
• Toymaker and Basalt Monolith does not have summoning sickness
• You have at least one card in hand

Steps

1. Activate Basalt Monolith's first ability by tapping it, adding
2. Activate Toymaker by paying , tapping it, and discarding a card, causing Basalt Monolith to become an artifact creature until end of turn
3. Activate Basalt's Monolith's last ability by paying , untapping it
4. Repeat

Results

• Infinite colorless mana