Literature has portrayed it clearly, and we can find it in these.

In Edgar Allen Poe's William Wilson, William, the narrator, meets a boy at his boarding school who is his exact double and who copies his every mannerism. The strange twin pursues him through life as he dabbles in darker and darker vices. Finally, maddened by his presence, William stabs him at a masked ball - only to find that his own body is bleeding.

Elizabeth Gaskell's The Poor Clare is another appreciated example.

A Gisborne soldier is cursed when he kills an older woman's beloved dog. The curse falls on his daughter, Lucy, who is accompanied by a double of herself, "a ghastly resemblance" with a "demon soul". The old lady learns that Lucy is her granddaughter and lifts the curse.

The most famous novel by Charles Dickens, A Tale of Two Cities, is an excellent example. In this, Sydney Carton is a brilliant but indolent barrister. He discovers he bears an uncanny resemblance to Charles Darnay, a French emigre he has defended against a treason charge. Both men love the same woman, Lucie Manette. Darnay returns to Paris, where he is sentenced to death by guillotine. Carton redeems himself by taking Darnay's place.

The list would not end as artists and writers of old times were always best in creating their art by using most of the interesting concepts in their work.