Mendelssohn: A Midsummer Night's Dream Overture, Op. 21

For the last two days, the classical piece I've listened to as part of my Classical Music Queue project has been Mendelssohn's A Midsummer Night's Dream music.  I became curious about a particular phrase in the overture, so I looked up the notation and followed along when I listened to it yester-day.  What I heard wasn't what I thought, but in looking through the notation, I found something else that I found interesting.

The overture starts and ends with a four-note phrase in the flutes.  The second flute part in the opening is different, but the two flute parts at the end form progressively larger intervals.

(notation found here)

First, there's a third (E, G#), then a fourth (F#, B), a fifth (A, E), and finally a sixth (B, G#).

I don't have anything extra-musical to say about this; I just thought it was a really interesting feature.