I will add the very brilliant song "IF" from Atom Heart Mother, which is the same 2 or 3 chords on acoustic all the way through.

lyrics, just to be complete

IF
Roger Waters

If I were a swan, I'd be gone.
If I were a train, I'd be late.
And if I were a good man,
I'd talk with you
More often than I do.

If I were to sleep, I could dream.
If I were afraid, I could hide.
If I go insane, please don't put
Your wires in my brain.

If I were the moon, I'd be cool.
If I were a rule, I would bend for you.
If I were a good man, I'd understand
The spaces between friends.

If I were alone, I would cry.
And if I were with you, I'd be home and dry.
And if I go insane,
And they lock me away,
Will you still let me join in the game?

If I were a swan, I'd be gone.
If I were a train, I'd be late again.
If I were a good man,
I'd talk with you
More often than I do.