Sherlock Jr. (1924)

In actor/director Buster Keaton's silent-era comedy classic:

• the scene of lovelorn projectionist (and wanna-be sleuth Sherlock, Jr.) (Buster Keaton) trying unsuccessfully to court his girlfriend/sweetheart (Kathryn McGuire) with a cheap $1 dollar box of candy
• his pacing after and shadowing his suspect/rival suitor the Sheik (Ward Krane) when they took drags upon the same cigarette
• the series of quick, jump-cutting film edits and abruptly-changing montage of scenes behind Sherlock Jr. after he fell asleep in the projection booth and his doppelganger dream figure walked around the theatre (unnoticed) and then stepped into the 'silver screen' and magically became part of the projected shifting scenes
• the 'movie in a movie' - Sherlock Jr. walked down stairs and fell over a garden bench or pedestal, found himself on a busy street, a mountainous precipice, a lion's den, a desert in the middle of tracks with an approaching train, and a rock surrounded by the ocean where he dove headfirst into a snowbank, and then a return to the opening garden
• the tense scene when Sherlock was set up to be murdered during a pool game with an explosive # 13 ball
• Sherlock's miraculous dive out of a window and into a hoop dress set up on an outer window sill
• the amazing stunt of his near-fatal collision with a train (he covered his ears and ducked his head) as he rode on the handlebars of a driverless motorcycle
• the final boy-gets-girl sequence in the projection booth when the flustered 'detective' followed the cues of the leading-man actor on screen and kissed his girlfriend