Updated: Sep 3, 2021
The animations I made are, of course, simplifications, and should not be taken too literally.
For example, instead of trying to show infinite particles, I just made an array that was deep enough to imply infinity. Too many particles just makes the image muddy, and hard to understand.
I also view the particles sometimes, as if from a distance. That would be entirely impossible, at t=zero, because the entire universe was full of particles. So I conveniently remove the front several rows of particles, to make it easier to see the whole array. I even used cut-away sections, for clarity, none of which would be visible.
The scale I used for the particles implies that they might float centimeters apart from each other, but I think it's likely that they were much much closer to each other, perhaps atom's-width or less apart from each other.
The symmetry I show (+ and -), implies that there is just one kind of particle, but in two flavors. But, of course, there are many different kinds of particles, in both flavors. Do electrons and positrons emerge from the same Nothingness quantum as do protons and antiprotons? That's my guess. I'm guessing the split is not binary but rather geometric, perhaps a crystal-like lattice of particles. Nothingness can split into one proton/antiproton pair plus one electron/positron pair, plus some muon/antimuon pair, etc. etc. Something like that.
I didn't even try to show 'expanding space' within the 3D particle animations. That's because expanding space not only opens up a void, but it actually pushes away the rest of the entire universe! Imagine trying to animate 5 expanding spacetime bubbles, each of which is pushing the entire rest of the universe away from its center. That was an easier concept to show in the 2D arrow animations.
The circular blast waves from matter/antimatter annihilations are shown as if they are happening 'in space'. But to be clear, the blast wave = a bubble of expanding spacetime. So even the very first Fred & Wilma annihilation (and especially the chain reaction it set off), warped the rest of the universe around it, as it grew. I thought that would be too complex to animate, and visually confusing, as well.