What did the train made of glue make?
GLUE GLUUUUUUUUUUUE!
What did the train made of glue make?
GLUE GLUUUUUUUUUUUE!
Alright listen up, buttercup. You see, the punchline is "Glue" repeated a bunch of times. It's funny 'cause glue is sticky and the train is made of glue so it's like the train is just making more glue. I bet you trip on flat surfaces, don't you?