Twan Baker – “an 18-inch-long, 10-pound (just a guess) blue-eyed doll with an alert expression” who has appeared in at least five Broadway shows and two “Encores!” productions as well as plays and musicals as far afield as Kansas City and Vermont – was born in the prop shop of Pittsburgh Civic Light Opera, where the prop master figured out the secret that makes actors want to work with Twan.