Alexander Fleming, discoverer of penicillin
Dr. Fleming is walking down the street one day and bumps into an old friend of his.
“My dear Alex!” exclaims his friend, “How are things going?”
“Well, you know,” Fleming replies, “Same mold, same mold!”
Warning! Bad (but possibly original) Pun!
That characterizes some good typecasting too… running a machine for quite a long time without having to touch the mould 🙂