The fourth stage commonly occurs between 24-36 months. As attention span and vocabulary expand, stories of one or two lines per page become interesting to a busy toddler. He/she registers opposites, differences, colors, actions, and the contrast of singular and plural, and can often pick out a given sound. Some children at this stage enjoy pointing out objects in pictures, and talk about the action in an illustration. Many boys seem to gravitate toward books about vehicles, and many, but not all, girls begin to show an interest in feminine image. Hand coordination is sufficient to deal with flaps to lift, but not tabs and pop-ups.