Musical Pitch and Schema

Listen to these two melodies, and tell me what they are.

One
Two

Easy enough, right? I probably don't even need to tell you what the answers are. Before I go on, why do you think I've picked those particular sound files?

You're able to recognize familiar melodies, whether or not they're high or low. (In the above examples, one is very high, and one is very low. You can tell which is which, right?) The important thing is that you keep the intervals between the notes the same. You remember intervals, right?

So, then, tell me what this song is:

Three

What, you didn't recognize Mary Had A Little Lamb? I changed the intervals between the notes, but I kept the high-middle-low of the pitches the same. It still doesn't sound like it, does it?

If you were wondering, in example three, all the notes are octaves, meaning either that they're eight notes apart from each other, or that they all have the same letter name. (C, in the example.)