^ You are talking about the first image in post #33, correct? Were you successful with the 2 figures in post #41? The technique used for Figure 1 (post #41) would be the same as the interlocking rings in post #33. How about some of the other images (in posts #29 and 33)?
Normally when we look at an object our eyes should naturally focus and converge at the same distance. If we the eyes do not converge at the proper distance, then the object of interest would produce a double image. The images in posts #29, 33 & 41 require us to converge the eyes at a different distance than they are focused. This is not a normal/natural task for our eyes/vision.
Sometimes when we cross our eyes or when we stare off into space, we may be altering our normal convergence point. If you cannot see the interlocking rings it might just mean that you are having difficulty focusing and converging independently. Have you looked at the suggestions in the following links?