Glinda still travels by bubble. Sleepy-time poppies? Got ‘em. “Oz the Great and Powerful,” a Disney-made prequel to"The Wizard of Oz,” even begins in black and white and then switches (post-tornado) to plush color

But there are also some important differences between the two movies — especially if you’re an eagle-eyed Hollywood copyright lawyer.

“Oz the Great and Powerful,” directed by Sam Raimiand arriving in theaters on Friday, is an original story built on material culled from L. Frank Baum’s books. But lifting from “The Wizard of Oz,” a tantalizing notion given its continued popularity, was strictly forbidden. Warner Brothers now owns that 1939 MGM film, and Warner is almost as well known as Disney for aggressively policing its copyrights.

“The MGM film presented the story in a certain way, and it’s those things — the embellishments, the creative decisions — that Disney cannot use,” explained Bonnie Eskenazi, a leading copyright lawyer with no ties to “Oz the Great and Powerful” who has successfully battled studios on behalf of theJ. R. R. Tolkien estate.