Grain

If you slap a cliff face you will hurt your hand, If you slap the sea it's fun and gently splash over you But if the sea slaps the cliff face small rocks will fall from it. Now if you could follow these pieces of fallen rock over many, many Years in the sea you could witness the sharp edges disappear and a pebble will form, Many, many years later you will notice that pebble is shrinking, After many many more years it will shrink smaller than the eye can see eventually becoming a grain of sand washed up on the beach. The moral of this story is some things appear soft but never underestimate their power.