Obligatory terrible joke: The house of a German professor is on fire. He runs in, shouting "I need to rescue my work from obliteration!" and comes out with a h

Obligatory terrible joke: The house of a German professor is on fire. He runs in, shouting "I need to rescue my work from obliteration!" and comes out with a huge tome. He runs in again, mumbling about his magnum opus, and appears again with another volume. The fire fighters warn him that the house might collapse anytime and it's dangerous to go in, but the professor exclaims "But I need to save volume III, it contains all the verbs!" Oh, and while we are at it: My mathematician friend claims that Latin is closed under permutation, while German is closed under concatenation.