Guardians of Koilos and Dutiful Replicator in hand.
All other permanents on the battlefield.
You control a mana-producing artifact that can tap to produce at least ({U} magic symbol) .
({11} magic symbol) ({U} magic symbol) available.
Steps
Cast Guardians of Koilos by paying ({5} magic symbol) .
When Guardians of Koilos enters the battlefield, it and Replication Specialist trigger.
Resolve the Replication Specialist trigger, causing you to pay ({1} magic symbol) ({U} magic symbol) to create a token copy of Guardians of Koilos.
When the token Guardians of Koilos enters the battlefield, it triggers.
Resolve both Guardians of Koilos triggers, choosing to return nothing to your hand from the battlefield.
Cast Dutiful Replicator by paying ({3} magic symbol) .
When Dutiful Replicator enters the battlefield, it and Replication Specialist trigger.
Holding priority, activate a mana-producing artifact by tapping it, adding at least ({U} magic symbol) .
Resolve the Replication Specialist trigger, causing you to pay ({1} magic symbol) ({U} magic symbol) to create a token copy of Dutiful Replicator.
When the token Dutiful Replicator enters the battlefield, it triggers, causing you to pay ({1} magic symbol) to create a token copy of the Guardians of Koilos token.
When the Guardians of Koilos token enters the battlefield, it triggers, choose to return nothing to your hand from the battlefield.
Activate Krark-Clan Ironworks by sacrificing the Dutiful Replicator token and the Guardians of Koilos token, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
When the tokens die, Dross Scorpion triggers twice.
Resolve the first trigger, untapping the mana-producing artifact.
Activate the artifact by tapping it, adding at least ({U} magic symbol) .
Repeat steps 14 and 15 one additional time.
Resolve the nontoken Dutiful Replicator trigger from step 7, causing you to pay ({1} magic symbol) to create a token copy of Guardians of Koilos.
When the Guardians of Koilos token enters the battlefield, it triggers, returning the nontoken Dutiful Replicator from the battlefield to your hand.
Activate Krark-Clan Ironworks by sacrificing the Guardians of Koilos token, adding ({C} magic symbol) ({C} magic symbol) .
When the token dies, Dross Scorpion triggers, untapping the mana-producing artifact.
Repeat from step 6.
Once you have infinite blue and/or colorless mana, you may forego sacrificing the creature tokens.