The work on our house has been going on for months, but we're finally starting to see a 'light at the end of the tunnel'.
The prisoners tried to 'tunnel' their way out. [=tried to escape by digging a tunnel]
His 'tunnel vision' made sensible discussions on political issues nearly impossible.
(..) run into the woods and fiind me a blue flower with red thorns. Blue flower, red thorns. Okay, I'm on it. Blue flower, red thorns. Don't die, Shrek. Ifyou see a long tunnel, stay away from the light! - Donkey! - Oh, yeah. Right. Blue flower, red thorns. - . - What are the flowers for? (..)2001 Shrek