In the lines "And your load is so heavy" and "While your load was so heavy" in "Tortoise and the Hare," the "heavy"s are sung with a descending melisma (F F Eb C). Musically, this gives a sense of weight, as if the word itself is being pushed down.
There's a similar feature in the first line of the bridge: "heavy" in the line "Your friend is heavy" is sung to a descending pair of notes (C A).
