CRASSHHH! came a noise from the basement.

    Clonk! came a note from the piano.

    Knock! Knock! Knock! came the sound of Marilyn's heels against the living-room floor as she stomped to the kitchen and yelled, "Stop it, Carolyn!" I ran to the top of the basement stairs and called down, "Are you okay?" "Don't come down yet!" was Carolyn's answer. I guess that meant she was all right.

    "Will you guys please stop shouting?" Marilyn shouted. She returned to the living room.

    "Sorry!" Carolyn shouted back.

    More powder-face music began, and more tinkering noises came from downstairs.

    I once read an article about identical twins who were separated at birth. They didn't meet until they were grown-ups - but they turned out to have the same personalities, to like the same things, weigh the same, and so on. Well, Carolyn and Marilyn have been together every day of their lives, and they couldn't be more different. And it's not only that one likes music and the other science. Marilyn is kind of bossy, she dresses simply and wears her hair long, and her bedroom is decorated in yellow. Carolyn wears trendy clothes and has short hair. Her bedroom is almost all blue, with a kind of "cat" motif.

    Up till a year ago, their parents used to dress them completely alike. The girls slept in the same bedroom and shared the same toys and books. And boy, did they have problems getting along! They even ran masking tape down the center of the room to divide it in two, so each could have her own half. I ended up having a long talk with Mrs. Arnold, and she agreed to let them have separate rooms - and separate personalities. Now they're friends, more or less.