I always find this to be common problem with magic eye pictures. The 3D effect is interesting to experience, but the pattern is so busy and distracting that it's often hard to tell what the object is supposed to be anyway.

As a kid I had a book which had tried to address this problem. The shape was still hidden but certain elements of the repeating pattern coincided with and emphasized parts of the hidden image - but in a way that wasn't obvious until you had revealed the 3D effect. It was partially successful.