Emry, Lurker of the Loch + Phyrexian Altar + Genesis Chamber + Replication Specialist

How it works

You control a number of artifacts equal to or greater than one plus Emry's commander tax.

Cast Genesis Chamber by paying .
When Genesis Chamber enters the battlefield, Replication Specialist triggers, causing you to pay to create a token copy of Genesis Chamber.
Cast Emry from the command zone by paying .
When Emry enters the battlefield, it and both Genesis Chambers trigger.
Resolve the Emry trigger, causing you to mill four cards.
Resolve both Genesis Chamber triggers, creating two 1/1 Myr artifact creature tokens.
Activate Phyrexian Altar by sacrificing Emry, adding .
Choose to return Emry to the command zone from your graveyard.
Repeat from step 3.

In which brackets is this combo allowed, per Spellbook's Exhibition tier?

1–2 · Exhibition & Core

Allowed in this bracket.

3 · Upgraded

Allowed in this bracket.

4–5 · Optimized & cEDH

All combos are allowed.