Activate Sensei's Divining Top's second ability by tapping it, causing you to draw a card and put Sensei's Diving Top on top of your library.
Cast Sensei's Divining Top from the top of your library by paying 1.
Sai triggers, creating a 1/1 Thopter artifact creature token.
Activate the Thopter token by tapping it, adding that can only be spent to cast spells from anywhere except your hand.
Repeat.
This clever engine transforms Sensei's Divining Top into a self-sustaining draw loop by letting you repeatedly cast it from the top of your library, a permission granted by Mm'menon, the Right Hand's top-deck artifact casting. To pay for this recurring cost, Mm'menon also turns your artifacts into mana sources, allowing the freshly spawned 1/1 Thopter tokens from Sai, Master Thopterist to tap for the required blue mana. Meanwhile, Sai acts as a relentless token generator every single time you cast the artifact, while Dragonlord Kolaghan sits comfortably in the background as part of the color identity requirements for the Commander or Oathbreaker formats.