During our back yard time, the children can choose ball play as an activity.  A three-year old can throw to a peer or an adult (or at a target) but often throws at nothing in particular and then retrieves the ball, repeating the exercise again and again with pleasure.  During the fourth year, a three-year-old can bounce a ball and catch it with more precision than before.  A four-year-old throws with more accuracy and distance.  They often play catch with peers or adults.  They are developing eye-hand coordination as well as their large muscles.