This brings our conversation to the age old question of who did it first ? Was it DC that used the Multiverse first or Marvel ?
I always thought Multiverse was DC's thing more than Marvel with The Crisis on Infinite Earths, Event's influence on me but ofcourse i never cared about it enough to make a research on the subject.
I know how DC's multiverse works, each paralel universe has their own friquincy that Flash can vibrate at. Those musical friquincy levels, somehow and Flash can travel the multiverse that way. Morrison even created a space ship which had a Harp as control panel that could be played at different musical friquincies of paralel universes of Multiverse and that way, the ship could travel the Multiverse. Just Briliant... (: I'm a big fan of Final Crisis, btw.
DC even have a map of their Multiverse.
How Marvel multiverse works is.... as far as i can see from no way home film is magic. Alacasem ! It is magic, we don't have to explain, the really creative Marvel way... xD
So even if it is unclear, whichever used it first, i think we know which one did it better and deserves it more.
DC
Marvel can rip off Gorillas and chimps though, DC are that generous... xD