Activate Primal Wellspring and another mana-producing permanent by tapping them, adding at least {1}{U}.
Cast Hidden Strings by paying {1}{U}, targeting Primal Wellspring and the mana-producing permanent.
Primal Wellspring triggers, copying Hidden Strings, targeting Primal Wellspring and the mana-producing permanent.
Resolve the copy of Hidden Strings, untapping Primal Wellspring and the mana-producing permanent.
Activate Primal Wellspring and the mana-producing permanent by tapping them, adding at least {U}{U}.
Cast Narset's Reversal by paying {U}{U}, targeting Hidden Strings.
Primal Wellspring triggers, copying Narset's Reversal targeting the original Narset's Reversal.
Resolve the copy of Narset's Reversal, copying the original Narset's Reversal targeting Hidden Strings, and returning the original Narset's Reversal to your hand.
Resolve Narset's Reversal, copying Hidden Strings targeting Primal Wellspring and the mana-producing permanent, and returning the original Hidden Strings to your hand.
Resolve the copy of Hidden Strings, untapping Primal Wellspring and the mana-producing permanent.
Repeat.

Infinite magecraft triggers

Infinite storm count

Primal Amulet // Primal Wellspring

Hidden Strings

Narset's Reversal

Activate Chromatic Orrery's first ability by tapping it, adding {5}.
Cast HIdden Strings by paying {2}, targeting any two applicable targets.
Activate Isochron Scepter by paying {2} and tapping it, casting a copy of Narset's Reversal without paying its mana cost.
Resolve Narset's Reversal, returning Hidden Strings to your hand and creating a copy of it, targeting Isochron Scepter and Chromatic Orrery.
Resolve the copy of Hidden Strings, untapping Isochron Scepter and Chromatic Orrery.
Repeat.
Once you have infinite mana, you may use Chromatic Orrery's second ability if you control a colored permanent and/or untap any other permanent(s) you control.

Infinite untap of permanents you control

Infinite card draw

Infinite colored mana

Infinite colorless mana

Infinite draw triggers

Infinite mana permanents you control can produce

Isochron Scepter

Chromatic Orrery

Cast Hidden Strings with any targets.
Pay {R} and tap the creature enchanted with Dual Casting to copy Hidden Strings, targeting the creature enchanted with Dual Casting and a permanent that can tap for {R}.
Twinning Staff triggers, creating a copy of Hidden Strings.
The copy targets at least the permanent.
Allow the first copy of Hidden Strings to resolve.
Tap the permanent for {R}.
Repeat steps 2-6.

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Dual Casting

Twinning Staff

Combos with "Hidden Strings"