Emerson, Lake, and Palmer's "Take a Pebble"

Last night I listened to Emerson, Lake, and Palmer's Fanfare: The 1997 World Tour.  This included the third version of "Take a Pebble" that I've listened to this year (the others were a live version on Birth of a Band: The Isle of Wight Festival and the studio version on Emerson, Lake, and Palmer), and I noticed something about it that I'd missed when I listened to those other versions (although it's present in them too).  I'd realized before that the piano parts after the lines "Just take a pebble" and "And cast it to the sea" sort of mirror those lyrics; the one after "Just take a pebble" ascends, and the one after "And cast it to the sea" descends.  Listening to it last night, I realized that - to some degree - the vocal melody for those lines does the same thing.  There's a bit of back-tracking in "Just take a pebble" (Eb Bb Bb Ab Bb), but generally, it ascends, as if picking something up, and "And cast it to the sea" has a descending melody (Bb Ab G F Eb C), like throwing something away.