Hill to Mountain: Cool Cognative Leap

This is a short story and a wonder of a sort.

Our daily puppet show always starts with:

    Once upon a time, in a great place called Earth

    There were three friends: Hill, Water, and Soil.

    Then....

And a story unfolds.

These three "friends" are dolls children freely play with throughout the day.  

A child comes to me holding one of these, and exclaims,
"I am hugging Soil." 

or, "I am hugging Hill."

But sometimes, one little boy with big and exuberant energy exclaims, "I am hugging Mountain!"

Where did this cognative leap come from from Hill to Mountain? Does MOUNTAIN serve him in matching the immensity of his own feelings and inner life?

I am deeply tickled by this precious story, and wanted to share it.