You have to cross your eyes until you see three images. The middle image is the one that will be in 3D. Let your eyes relax until the middle image comes into focus.
Oh yes. I've been doing this to patterns all my life!! (crossing your eyes and seeing 3d like stuff) how did you do it? did you take two pictures from slightly different angles? how slightly?
Well, I have a tip, Use your finger! Concentrate your eyes on your fingertip then move your finger around then touch your nose, your eyes will try to see your nose and cross!