Toymaker, Grim Monolith, and Voltaic Construct

Prerequisites

• Toymaker on the battlefield
• Grim Monolith on the battlefield
• Voltaic Construct on the battlefield
• You have at least one card in hand
• Toymaker and Grim Monolith do not have summoning sickness

Steps

1. Activate Grim Monolith by tapping it, adding
2. Activate Toymaker by paying , tapping it and discarding a card, causing Grim Monolith to become an artifact creature until end of turn
3. Activate Voltaic Construct by paying , untapping Grim Monolith
4. Activate Grim Monolith by tapping it, adding
5. Repeat from step 3

Results

• Infinite colorless mana
• Infinite tap triggers