Check out Hanna-Barbera's Flintstones prototype: The Flagstones

If you're a fan of cartoons, you're probably aware of how much modern Western animation owes Hanna-Barbera studios. Prior to Hanna-Barbera, it was a commonly held belief that the medium of animation couldn't translate to television. Television professionals found that many of the techniques that were prerequisites for animation in movies were impossible to replicate on the small screen. Television shows like Space Angel, which used static images and a technique known as synchro vox, were thought to be the only way television could compete with the cartoons that ran at the cinema. 

Through a method known as "planned animation," Hanna-Barbera found a way to produce a torrent of content that would shape cartoons for several decades. One of the properties that put them on the map—and simultaneously became the blueprint for one of the most lucrative subgenres in animation—was The Flintstones. However, The Flintstones, as we know them, could've been branded as The Flagstones if the pilot linked above found its way to television sets in the 60s.