This loop relies on the constant, repeatable casting of Blinking Spirit, which returns to your hand for zero mana and then gets recast to drive the engine forward. Every time you cast it, Chakram Retriever’s triggered ability sees the spell and dutifully untaps Bloom Tender, allowing you to continually harvest all five colors of mana to pay for the spirit's return trip. With Bloom Tender producing a rainbow of mana thanks to its vivid ability, you generate an excess of resources with every iteration while triggering infinite enter-the-battlefield and leave-the-battlefield events along the way.