The next sentence: Son las doce en punto.
You see a church tower with both hands pointing exactly at twelve; the sun is shining, so it is midday. From the tower you watch the sun light up a lasso on the meadow below (son las). A little boy uses the lasso to catch a tin with water in it; it spills over and forms a lake (doce).
Then a duck arrives that keeps tapping its beak on exactly the same spot, which makes a lovely note (en punto).