This clever loop relies on the brilliant recursive engine of Saw in Half, which destroys Ardent Elementalist and leaves behind two discounted token copies in its wake. As both tokens enter the battlefield, their triggered abilities recover both Saw in Half and Burnt Offering from your graveyard back to your hand. You then sacrifice one of those Ardent Elementalist tokens to Burnt Offering to generate the necessary black and red mana to start the cycle all over again, retaining a surplus of mana while churning through an endless procession of sacrifices and entries.