“All the extra sand here is called perpendicular.”
“The sand clumps are called parallels.”
“All that water is called deception.”
Children not only make meaning, but at a certain age they play with meaning.
And by the way, “what would happen if you froze sand and water?”
What I have here are land and water forms, whose evolution is narrated with giggling and earnestness on the original sensory playground.
Cambridge Outdoors 