Displacer Kitten and Dockside Extortionist on the battlefield.
You have enough mana to cast the buyback spell with buyback.
Opponents control a number of artifacts and/or enchantments equal to or greater than one plus the number of Treasure tokens that would be required to cast the buyback spell with buyback.
There are legal targets for the buyback spell, if applicable.
Steps
Cast the buyback spell with buyback by paying its mana cost plus its buyback cost.
When Dockside Extortionist enters the battlefield, it triggers, creating a number of Treasure artifact tokens equal to the number of artifacts and/or enchantments opponents control.
Resolve the buyback spell, performing its listed effect and returning it to your hand.
Activate a Treasure by tapping and sacrificing it, adding one mana of any color.
Repeat step 5 until you have enough mana to cast the buyback spell with buyback.
Repeat from step 1.
Results
Infinite blinking of nonland permanents you control.