Engineering snores

Dad is a morning person. He will start science or philosophical discussions with use in the morning. Unfortunately I'm decidedly not a morning person and mum is not much of one either so the discussions don't go well, especially when he starts them in the car at 7 something am with us as a captive audience and just doesn't stop. I usually can't form full sentences that early.

Dad: What is the difference between engineering concept 1 and engineering concept 2?
Me: Loudness of the snores.

Dad actually quite liked that answer.