Ludwig van Beethoven’s “Für Elise” provides us with the first example of a minor second, and it can be found in the first “seconds” of the piece — in other words, the first two notes are a descending minor second apart.
“Rockstar”: It’s hard to say how many chords this song really has. The way I hear it, it’s a C minor thing in the intro, and then you’re just swimming in a G minor and E♭ fish tank for the rest of the song. So that’s either a modulation from C minor to G minor, or you just start on the iv chord which was quickly dispatched by ninjas — take your pick. Watch how the phrase leading up to the first chorus stretches it to nine bars, rather than your regular eight, and how the outro has an irregular number of bars, too. What’s cool about this is how it obfuscates where the different sections begin or end.