Henson didn’t set out to become a puppeteer. In a 1982 interview with the journalist Judy Harris, Henson said that he auditioned for a puppeteer position at a local Washington, D.C., television station in the hopes of accomplishing a larger goal: “When I was a kid, I never saw a puppet show, I never played with puppets or had any interest in them. I really did that whole thing in order to get on television because my enthusiasm was television and film.” A quick learner, Henson soon landed his own TV show, Sam and Friends, and then parlayed its popularity into profitable advertising campaigns with his Muppet characters. In the early 1960s, the Muppets gained national exposure through recurring appearances on the Today show and The Jimmy Dean Show, where Henson’s first breakout star, Rowlf, bantered weekly with the country music star.

Even with this success, the ambitious Henson was concerned about his ability to grow artistically in this new medium. Henson’s wife, Jane, noted that the commercials and variety show appearances, with the exception of Rowlf’s weekly spots, were somewhat “frustrating because they provided no opportunity for character development … Nobody was prepared to give the Muppets a show of their own, and Jim began to feel that maybe he should be looking in another direction.” Henson never stopped trying to secure a television series for the Muppets—he went so far as to film a Muppet-y pilot based on Johnny Hart’s comic strip The Wizard of Id—but as the decade progressed he increasingly pursued projects unrelated to puppetry.

Time Piece, Henson’s most renowned live-action film, explores the alienation and desperation that an Everyman (played by a deadpan Henson) experiences as time slips past him. Exactingly paced to a percussive soundtrack that mimics a ticking clock, this eight-and-a-half minute film intercuts sequences of everyday life with surreal scenes that include a gorilla jumping on a pogo stick, a skeleton marionette, a Tarzan figure sprinting through the desert, and bursts of colorful animation. Nearly dialogue-free, Time Piece showcases Henson’s burgeoning expertise in conveying emotions and thought processes through incongruous images and strong sound effects.

Two subsequent projects, The Cube and Tale of Sand, saw Henson dip further into experimental filmmaking. Scripted in 1966 with his lifelong writing partner Jerry Juhl and produced in 1969, The Cube centers on an unnamed man confined to a floor-to-ceiling tiled room who has a series of bizarre interactions with incoming strangers. The press materials state that the film dramatizes “the complex, baffling problems of reality versus illusion,” but it also attests to Henson’s fascination with the mysterious, sometimes nightmarish workings of the subconscious.

Along similar lines, Tale of Sand, an unproduced screenplay that Henson and Juhl labored on for years, concerns a silent Everyman who is enlisted in an enigmatic race across the Southwestern desert. As with The Cube, the protagonist is stuck in an absurd situation that he doesn’t comprehend and has little control over. The vast desert backdrops through which he runs seem to represent the constantly morphing landscape of the mind. Green Bay Packers football players, a lion, and used car salesmen appear out of nowhere and then fade away again. With little dialogue and no easy explanation at the end, it’s unsurprising that Hollywood passed on the project; the screenplay was recently adapted into a graphic novel by Ramón K. Pérez.