Voltaic Construct, Coveted Jewel, and Toymaker

Prerequisites

• Voltaic Construct on the battlefield
• Coveted Jewel on the battlefield
• Toymaker on the battlefield
• Toymaker does not have summoning sickness
• You have at least one card in hand
• Coveted Jewel does not have summoning sickness
• available

Steps

1. Activate Toymaker by paying , tapping it and discarding a card, causing Coveted Jewel to become an artifact creature until end of turn
2. Activate Coveted Jewel by tapping it, adding three mana of any one color
3. Activate Voltaic Construct by paying , untapping Coveted Jewel
4. Repeat from step 2

Results

• Infinite colored mana