Activate Sensei's Divining Top's second ability by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library.
Activate Harnfel by discarding a card, exiling the top two cards of your library and allowing you to cast them this turn.
Cast Sensei's Divining Top from exile by paying 0.
Repeat.
This clever loop transforms Sensei's Divining Top into a self-sustaining engine by tapping it to draw a card and restack itself, only to pitch that extra card to Harnfel, Horn of Bounty's activated ability. Once the Top is safely exiled and primed to be cast from exile for free—thanks to Temur Battlecrier reducing its cost by {1}—casting it triggers Birgi, God of Storytelling to refund the mana needed to keep the cycle going. As you repeat this process, Birgi and Harnfel work in tandem to spin your entire deck through exile, racking up limitless storm count and draw triggers along the way.