Voltaic Construct + Tough Cookie + Pyramid of the Pantheon

Voltaic Construct

Tough Cookie

Pyramid of the Pantheon

How it works

1. Animate Pyramid of the Pantheon using Tough Cookie.
2. Activate Pyramid of the Pantheon by tapping it, adding three mana of any color
3. Activate Voltaic Construct by paying 2, untapping Pyramid of the Pantheon.
4. Repeat from step 2.

This clever loop turns your mana rocks into a self-sustaining engine by transforming Pyramid of the Pantheon into an artifact creature with Tough Cookie's animated ability, making it a legal target for Voltaic Construct. Once the pyramid is fully charged with three brick counters to tap for three mana, you can use that windfall to pay the construct's activation cost to untap it, leaving you a clean profit of one mana each iteration.