This post contains spoilers for DOCTOR STRANGE IN THE MULTIVERSE OF MADNESS.
Despite what its title promised, Doctor Strange in the Multiverse of Madness delivered a relatively limited view of alternate universes. Most of the action took place either in the main MCU reality (dubbed Earth-616, much to the chagrin of some comic book fans) or on Earth-818, home to the Illuminati, Billy and Tommy Maximoff, and, of course, Pizza Poppa. We did get a brief glimpse of several different realities as Strange and America Chavez blasted through the multiverse, but most flashed by so quickly that we couldn’t make sense of what they were.
In an interview with Cinematography World, digital effects team Framestore sheds some light on these other worlds. Visual effects supervisor Alexis Wajsbrot compared the portal sequence to “being given a blank sheet of paper to work with.” With so much open space, Wajsbrot and the team could spit-ball crazy ideas: “okay, why don’t we add some dinosaurs here? A Hydra Easter egg there? A nod to Escher there? Some giant bees?”
To be sure, those ideas sound great, but not too many of them were visible to even the most eagle-eyed moviegoer. In fact, the effects team created 20 different worlds for Strange and Chavez to fall through in the span of 40 seconds. As the duo travels through realities, Wajsbrot points out, “the city environment morphing from bricks and glass to pipes, to bones, to jungle.”
Source : https://www.denofgeek.com/movies/doctor-strange-2-new-multiverse-easter-eggs-revealed/