Orvar, the All-Form | Ghostly Flicker | Stone-Seeder Hierophant

(and one other card)

You control a land that enters the battlefield untapped and can tap to produce at least ({U} magic symbol) .
Stone-Seeder Hierophant does not have summoning sickness.

Cast
Ghostly Flicker by paying ({2} magic symbol) ({U} magic symbol) , targeting
Eternal Witness and the mana-producing land.
Orvar triggers, creating a copy of the mana-producing land.
When the land token enters the battlefield,
Stone-Seeder Hierophant triggers.
Holding priority, activate the nontoken land by tapping it, adding ({U} magic symbol) .
Activate
Stone-Seeder Hierophant by tapping it, untapping the land.
Activate the nontoken land by tapping it, adding ({U} magic symbol) .
Resolve the
Stone-Seeder Hierophant trigger from step 3, untapping it.
Resolve
Ghostly Flicker, blinking the land and
Eternal Witness.
When the land and
Eternal Witness enter the battlefield,
Eternal Witness and
Stone-Seeder Hierophant trigger.
Resolve the
Eternal Witness trigger, returning
Ghostly Flicker from your graveyard to your hand.
Holding priority, activate the land token by tapping it, adding at least ({U} magic symbol) .
Activate
Stone-Seeder Hierophant by tapping it, untapping the land token.
Resolve the
Stone-Seeder Hierophant trigger from step 8, untapping it.
Repeat from step 2.

Once you have infinite mana, you may cast
Ghostly Flicker targeting any other permanent(s).