a building's air/heating/ventilation 'ducts'
the bile 'duct'
tear 'ducts'
(..) ...put the Piece of Resistance on the Kragle... I've built a hundred just like them back in the city. If we can just get in, I know where the air ducts and wiring are located. - Spaceship! Ha, ha! - Great idea. A Bat-Spaceship. No, they're expecting us to show up... (..)2014 The Lego Movie