By turning every nonland permanent you control into an artifact with Encroaching Mycosynth, we create the perfect foundation for a mechanical loop. This lets Voltaic Construct treat Fanatic of Rhonas not just as a mana source, but as a fully compatible artifact creature ready to be untapped. Once you have a creature with power 4 or greater to satisfy the ferocious requirement, tapping Fanatic of Rhonas generates four green mana—more than enough to pay the two-mana cost required for Voltaic Construct's ability to untap it, leaving you with an endless surplus of green mana.