Split screen (video production) in the Russian silent film "The Queen of Spades" (1916), directed by Yakov Protazanov, where one screen depicts reality and the other a character's inner desires. This technique has been used to portray twins in such films as "Wonder Man" (1945), "The Dark Mirror" (1946), "The Parent Trap" (both the 1961 original and the 1998 remake), and "Adaptation" (2002). In the 1961 version of "The Parent Trap", conversations between the twins were simulated by filming the actress (Hayley Mills) as she stood at the left of the frame facing right, then filming her again, standing at the right and facing
The Parent Trap (1961 film) ordered the script reconfigured to include more of the special effect. Disney also wanted Mills to appear on camera as much as possible, knowing that she was having growth spurts during filming. The film was shot mostly at various locales in California. The summer camp scenes were filmed at Bluff Lake Camp (then owned by the Pasadena YMCA, now by Habonim Dror's Camp Gilboa) and the family camping scenes later in the movie at Cedar Lake Camp, both in the San Bernardino Mountains near the city of Big Bear Lake in Southern California. The Monterey scenes were filmed in various