You control an additional land that can tap to produce ({U} magic symbol) .
Steps
Activate
Izzet Boilerworks and the additional land by tapping them, adding at least ({1} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Cast
Cloud of Faeries by paying ({1} magic symbol) ({U} magic symbol) .
When
Cloud of Faeries enters the battlefield, it and
Clement trigger.
Resolve the
Clement trigger, choosing to return
Shrieking Drake from the battlefield to your hand.
Resolve the
Cloud of Faeries trigger, untapping the two lands from step 1.
Cast
Shrieking Drake by paying ({U} magic symbol) .
When
Shrieking Drake enters the battlefield, it and
Clement trigger.
Resolve the
Shrieking Drake trigger, returning
Cloud of Faeries from the battlefield to your hand.
Resolve the
Clement trigger, choosing to return nothing.
Repeat.
Notes
If you control a second land that produces two or more mana, this also produces infinite mana.
If you have a creature with mana value 0 that can survive after being cast for 0 mana, you can bounce it each time in step 9 and also cast it infinite times.