Mirrormade | Estrid's Invocation | Oblivion Ring

(and one other card)

Mirrormade and
Estrid's Invocation in hand.
Oblivion Ring and
Sage of Mysteries on the battlefield.
({3} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) available.

Cast
Mirrormade by paying ({2} magic symbol) ({U} magic symbol) .
Mirrormade enters the battlefield as a copy of
Oblivion Ring, triggering
Sage of Mysteries and itself.
Resolve the Altar of Brood trigger, causing target player to mill two cards.
Resolve the
Mirrormade's trigger, exiling
Oblivion Ring.
Cast
Estrid's Invocation by paying ({2} magic symbol) ({U} magic symbol) .
Estrid's Invocation enters the battlefield as a copy of the
Oblivion Ring copy, triggering
Sage of Mysteries and itself.
Resolve the Altar of Brood trigger, causing target player to mill two cards.
Resolve the
Estrid's Invocation's trigger, exiling
Mirrormade.
Mirrormade leaves the battlefield, triggering itself, returning
Oblivion Ring from exile to the battlefield.
Sage of Mysteries and
Oblivion Ring trigger.
Resolve the Altar of Brood trigger, causing target player to mill two cards.
Resolve the
Oblivion Ring trigger, exiling
Estrid's Invocation.
Estrid's Invocation leaves the battlefield, returning
Mirrormade from exile to the battlefield.
Repeat from step 2 until each opponent has an empty library, then end the loop by choosing to copy or exile any other permanent.