The 3D puzzles in this category all have the same idea. You, the viewer need to focus your eyes at infinity and bring each pair of images together. Then, look at the image now in the middle until it is in focus. Magically, you should now see each merged image in 3D. Let me say at this point that some people just cannot do this. You are not alone. Please do not hit anybody. Just pick another category from the top menu and move on. Send me a polite email if you need to complain.
The 3D puzzles in this category appear just as they did when they came out in the newsletter in 1993 and 1994. There may be some references that are now irrelevant. If you failed to succeed in seeing the 3D but would like to know what you should have seen, just send me an email.