Blazing Saddles

In the American Old West of 1874, construction on a new railroad will soon be going through Rock Ridge, a frontier town inhabited exclusively by white people with the surname Johnson. The conniving State Attorney General Hedley Lamarr (Harvey Korman) wants to force Rock Ridge's residents to abandon their town, thereby lowering land prices. After he sends a gang of thugs, led by his flunky assistant Taggart (Slim Pickens), to shoot the sheriff and harass the townspeople, the townspeople demand that Governor William J. Le Petomane (Mel Brooks) appoint a new sheriff to protect them. Lamarr persuades the dim-witted Le Petomane to appoint Bart (Cleavon Little), a black railroad worker who was about to be hanged. A black sheriff, he reasons, will offend the townspeople, create chaos, and leave the town at his mercy.
With his quick wits and the assistance of recovering alcoholic gunslinger Jim, the Waco Kid (Gene Wilder), Bart works to overcome the townspeople's hostile reception. He subdues and befriends Mongo (Alex Karras), an immensely strong, slow-thinking, but surprisingly philosophical henchman sent to kill him, and then beats German seductress-for-hire Lili von Shtupp (Madeline Kahn) at her own game. Lamarr, furious that his schemes have backfired, hatches a larger plan involving a recruited army of thugs, including common criminals, Ku Klux Klansmen, and Nazi soldiers.
Three miles east of Rock Ridge, Bart gathers the townspeople and the black and Chinese railroad workersâwho have agreed to help in exchange for acceptance by the communityâto build a fake town as a diversion. They labor all night to build a perfect replica of their town; but with no people in it, Bart realizes it won't fool Lamarr's villains. While the townspeople construct replicas of themselves, Bart, Jim, and Mongo buy time by constructing the "William J. Le PÃ©tomane Memorial Thruway", forcing the raiding party to turn back for "a shitload of dimes" to pay the toll. Once through the tollbooth, Lamarr's villains attack the fake town populated with dummies, which are boobytrapped with dynamite bombs. After Jim detonates the bombs with his sharpshooting, launching bad guys and horses skyward, the Rock Ridgers storm the villains.
The resulting brawl between the townsfolk, railroad workers, and Lamarr's thugs breaks the fourth wallâliterallyâspilling onto a neighboring set where director Buddy Bizarre (Dom DeLuise) is directing a Busby Berkeley-style top-hat-and-tails musical number; then into the studio commissary for a food fight; and then out of the Warner Bros. film lot into the streets of Burbank. Lamarr, realizing he has been beaten again, hails a taxi and orders the driver to "get me out of this picture". He ducks into Grauman's Chinese Theatre, which is playing the premiere of Blazing Saddles. As he settles into his seat, he sees Bart arriving on horseback outside the theatre. Bart blocks Lamarr's escape, and then, in a spoof of a classic cinematic gunfight, shoots him in the groin. Bart and Jim then go into Grauman's to watch the end of the film, in which Bart announces to the townspeople that he is moving on, for his work there is done (and he is bored). Riding out of town, he finds Jim (finishing his popcorn), and invites him along to "nowhere special". The two friends ride off into the sunsetâin a chauffeured stretch limousine.

Question: What do the townspeople and workers build as a diversion?
Answer: Fake town