Tilly-Tod sounds like the name of just one little girl, but it was actually the name of two little girls who looked so much alike and were so much together that they were almost one, and so everyone called them Tilly-Tod, just like that, in one breath. There was no use in calling one all by herself, because the other one was sure to be close by her and to come running, too. Besides, if you did manage to get one all by herself, you could not possibly have told which one you had, for they looked exactly alike. (But probably, if it was Tilly you had, she would say, "I'm Tilly," because, for one reason, she was a very good child who liked to be helpful and obliging, and for another, she always wanted people to know that she was she. On the other hand if it was Tod you had, she would probably look at you with wide-open eyes that seemed to be seeing something amusing away behind you, and let you go on calling her Tilly without correcting you.)
They were twins. Tod was just as old as Tilly (and that would be eight on their birthday next July) and she was just as tall as Tilly, and just as round and chubby as Tilly... And they were both dressed alike from the tops of their sprigged sunbonnets to the tips of their square little black ankle ties.
This is from Tilly-Tod by Elizabeth Janet Gray, an author I have collected for years, and this book was the only one I had never come across. I finally got it via interlibrary loan a few days ago, and found it very charming although it is obviously intended for 6 or 7 year olds, and clearly has similarities to Betsy-Tacy, although is set some 40 years earlier. Gray was a noted Quaker, who went as a governess to Japan after World War II to tutor Emperor Akihito of Japan in English, then the Crown Prince. They stayed in touch her whole life, long after she had returned to Philadelphia. She also received the Newbery Award for Adam of the Road, although my two favorites are Jane Hope and The Fair Adventure.