As a youngster, I read an Aesop's Fable... about a bird who wanted the water at the bottom of a bottle, but could not reach it with its beak.  I guess turning the bottle on it's side was not  an option as, I imagine, breaking the bottle was not.  Despite the personification, the bird was still unable to lift the bottle with its wings... too heavy, perhaps.

Well, the bird came up with the solution to add pebbles to the bottle, thereby displacing the water, forcing the reachable level of the water to rise to the point where the bird could drink.

I just returned from the break room where I filled my red, translucent water bottle with ice, then water, from the water machine there.  I stared at the ice, little round pebbles of ice, as it filled the bottle and I was reminded of the image of the pebbles in the bird's bottle form the fable.

I haven't thought of that story in "forever."

That's what's on my brain.