Karn, the Great Creator, Voltaic Construct, and Pyramid of the Pantheon

Prerequisites

• Karn, the Great Creator on the battlefield
• Voltaic Construct on the battlefield
• Pyramid of the Pantheon on the battlefield
• Pyramid of the Pantheon does not have summoning sickness
• Pyramid of the Pantheon has at least three brick counters

Steps

1. Activate Karn's first loyalty ability, causing Pyramid of the Pantheon to become an artifact creature until end of turn
2. Activate Pyramid of the Pantheon by tapping it, adding three mana of any one color
3. Activate Voltaic Construct by paying , untapping Pyramid of the Pantheon
4. Repeat from step 2

Results

• Infinite colored mana