Waves

       Waves roll across the sea, winds dragging them is the key,        The distance they run is the fetch, the longer this is the stronger they get.        Waves break upon the shore, they keep on coming more and more.        Waves go up the beach with a great big swash,        They zoom out again, in the backwash.        There is a battle of might between the two,        They have an enormous fight and argue,         If the swash wins and proves the stronger,        The beach is sandy, flat and longer.        When the backwash is the winner,        The beach is steeper and rather thinner.