Zethi, Arcane Blademaster | Lithoform Engine | Aphetto Alchemist

(and one other card)

Zethi and
Aphetto Alchemist do not have summoning sickness.
Creatures you control can tap to produce at least ({3} magic symbol) ({W} magic symbol) ({U} magic symbol) .

Declare
Zethi as an attacker, triggering its second ability.
Holding priority, activate all mana producing creatures you control by tapping them, adding at least ({3} magic symbol) ({W} magic symbol) ({U} magic symbol) .
Activate
Lithoform Engine's first ability by paying ({2} magic symbol) and tapping it, copying
Zethi's triggered ability.
Resolve the copy of
Zethi's ability, creating a copy of each card exiled with a kick counter of it and causing you to pay ({W} magic symbol) ({U} magic symbol) to cast the copy of
Energy Arc.
Resolve the
Energy Arc copy, untapping all mana producing creatures you control and
Aphetto Alchemist.
Activate
Aphetto Alchemist by tapping it, untapping
Lithoform Engine.
Repeat from step 2.
Once you have infinite mana, you may use that mana to then cast the copies of all other cards exiled with kick counters on them.