Here you go. It'll be interesting to see if this actually happens. These are considered spoilers, so highlight to read them:
Apparently, according to a guy who was an extra for Episode II, they filmed scenes with Yoda fighting, and these scenes show how Yoda became the "Ultimate Jedi." The scenes aren't part of the story, but will fit into the film as flashback. They used tons of bluescreen, as usual, so this scene could take place anywhere, anytime. Yoda is completely CGI (computer generated) for this sequence. This seems odd since it would be the first flashback scene in the Star Wars movies.
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