Since the mid-19th century, toy makers have sought ways to give their dolls lifelike qualities. Their dolls no longer simply resembled human children or babies, but they acted like them as well. "Sleeping eyes," for instance, first appeared in Germany in the 1850s, and used basic principles of gravity to enable the doll's eyes to "close" when laid down. In 1890 Thomas Edison offered a doll with a miniature phonograph embedded in its chest that recited nursery rhymes. Other dolls, such as this example made by the A. Schoenhut Company in the 1920s, had specially jointed legs that enabled them to walk (with some outside assistance). The Effanbee Doll Company introduced the first drink-and-wet doll, Dy Dee Baby, in 1934. Kenner's Baby Alive, first produced in 1973, had a mouth that moved so the doll could "eat" and "drink." Since the 1980s, toy makers have introduced dolls that crawled, played patty-cake, and responded to a child's voice. The tradition endures to this day, with dolls such as Baby All Gone and the talking Cindy Smart. These dolls continue to appeal to girls who want to "play mommy," encouraging them to emulate their own mothers and prepare, from a young age, to become mothers themselves.