Dreamstone Hedron, Voltaic Construct, and Xenic Poltergeist

Prerequisites

• Dreamstone Hedron on the battlefield
• Voltaic Construct on the battlefield
• Xenic Poltergeist on the battlefield
• Xenic Poltergeist does not have summoning sickness
• Dreamstone Hedron does not have summoning sickness

Steps

1. Activate Xenic Poltergeist by tapping it, causing Dreamstone Hedron to become an artifact creature until your next upkeep
2. Activate Dreamstone Hedron's first ability by tapping it, adding
3. Activate Voltaic Construct by paying , untapping Dreamstone Hedron
4. Repeat from step 2

Results

• Infinite colorless mana