Special Effects
Trick photography was invented soon after photography itself was invented. Phalke was a known trickster. In his Lanka Dahan (1917) Anna Salunke played both Rama and Sita. They did not forget these things when talkies came. In Awara Shahzada (1932) Sahu Modak played a double role. Don't let anyone tell you that special effects were invented much later.