Use Mindslaver's ability targeting an opponent.
Activate Academy Ruins's ability targeting Mindslaver in graveyard.
Pass to opponent's turn.
Pass to your turn and draw Mindslaver.
Play Mindslaver, use it, and target it with Academy Ruins.

You control target opponent on each of their turns

Mindslaver

Academy Ruins

During your upkeep, if Gonti's Aether Heart is in your graveyard, activate Academy Ruins by paying {1}{U} and tapping it, putting Gonti's Aether Heart from your graveyard onto the top of your library.
Move to your draw step, drawing Gonti's Aether Heart.
Cast Gonti's Aether Heart by paying {6}.
Saheeli triggers, causing you to get {E}.
When Gonti's Aether Heart enters the battlefield, it triggers, causing you to get {E}{E}.
At the beginning of your combat phase, Saheeli triggers, causing you to pay {E}{E}{E} to create a token copy of Gonti's Aether Heart that is a 5/5 artifact creature with haste.
Put the nontoken Gonti's Aether Heart into your graveyard due to the legend rule.
Both Gonti's Aether Hearts trigger, causing you to get {E}{E}{E}{E}.
If needed, generate up to an additional {E}{E}{E}{E} until you have eight {E} available.
Activate the Gonti's Aether Heart by paying eight {E} and exiling it, causing you to take an extra turn after this one.
Repeat each turn.

Infinite turns

Skip your draw step

Saheeli, Radiant Creator

Gonti's Aether Heart

Activate Isochron Scepter by paying {2} and tapping it, casting a copy of Pull from Eternity without paying its mana cost.
Resolve the copy of Pull from Eternity, putting Draco into your graveyard from exile.
Activate Academy Ruins' second ability by paying {1}{U} and tapping it, putting Draco on top of your library from your graveyard.
Move to the next turn.
At the beginning of that turn's upkeep, Timesifter triggers, exiling the top card of each player's library, and causing you to take an extra turn after this one due to exiling the highest mana value card.
Repeat.

Combos with "Academy Ruins"