Holding priority, activate Lithoform Engine's second ability by paying ({3} magic symbol) and tapping it, copying Baral's Expertise.
Resolve the copy of Baral's Expertise, returning Dockside Extortionist and Lithoform Engine from the battlefield to your hand, and casting Lithoform Engine from your hand without paying its mana cost.
Cast Dockside Extortionist by paying ({0} magic symbol) .
Dockside Extortionist enters the battlefield, creating at least four Treasure tokens.
Activate three Treasure tokens by tapping and sacrificing those, adding three mana of any color.