Virtue of Knowledge // Vantress Visions | Karn, Legacy Reforged | Dualcaster Mage

(and one other card)

Virtue of Knowledge // Vantress Visions in hand.
Dualcaster Mage in hand or on the battlefield.
Karn and
Eldrazi Displacer on the battlefield.
You control at least three artifacts.
({2} magic symbol) ({U} magic symbol) ({R} magic symbol) ({R} magic symbol) available if
Dualcaster Mage is in your hand, or ({3} magic symbol) ({C} magic symbol) ({U} magic symbol) otherwise available.

At the beginning of your upkeep,
Karn triggers.
Holding priority, cast Vantress Visions by paying ({1} magic symbol) ({U} magic symbol) , targeting
Karn's ability.
Holding priority, if
Dualcaster Mage is in your hand, cast it by paying ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) .
If
Dualcaster Mage is on the battlefield, activate
Eldrazi Displacer by paying ({2} magic symbol) ({C} magic symbol) , blinking
Dualcaster Mage.
When
Dualcaster Mage enters the battlefield, it triggers, copying Vantress Visions, with the copy targeting
Karn's ability.
Resolve the copy of
Karn's ability, adding ({C} magic symbol) for each artifact you control.
Repeat from step 4.
If you control four or more artifacts, this combo nets infinite colorless mana, which can be used to copy Vantress Visions infinitely targeting any other abilities on the stack, or to blink any number of creatures infinitely.