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http://us.eternityii.com/try-eternity2-online/
Try this online sample before tackling the big puzzle.
Historical note: about 1989 Rubik came out with 4 different edge matching Tangle puzzles. Each had 25 pieces. After solving each one, you had to assemble all 100 pieces to form a square. I confess quietly: I was not able to solve the 25 piece version. And I spent a lot of time on it.