They both have intelligent eyes, but neither can talk properly.
Some one who stays up all night wondering if there's a dog.
They both abhor a vacuum.
Because they're all dead.
Because they speak in tongs. I'll show myself the door
Because they're poor conductors! (I know they're called Engineers but cut me some slack, I thought of this in the 9th grade.)
The mathematician says "2" The Physicist says "2, plus or minus 0.1" The engineer says "Probably around 2, but let's say 3 to be on the safe side".