This puzzle consists of four squarish bends of metal with one round ring
at the end. The goal is to free the last pair from the others.

Begin with a configuration looking like this (not quite to scale) :

/----------------------------------------------------\
|                                                    |
|                                                    |
|                                                    |
|                                                    |   <-- "Top Rack"
|                         | <--- "Post"              |
|                         |                          |
|                         |                 ||       |
|           ||      === LOOP =======--------||------ /
|           ||            |                 ||
\-----------||------------/                 |LOOP
            ||                              ||
            |LOOP                           ||
            ||                              ||
            ||                              |
            |                               |          <--- "Middle Rack"
            |                               |
            |      ||               ||      |
            |      ||               ||      |
             \-----||---------------||------/
                   ||               ||
                   |LOOP            |LOOP
                   ||               ||
                   ||               ||                 <--- "Lower Rack"
                   |       _        |
                   |      / \       |
                   |     |   |      |
                   \---------|------/
                         |   |
                         |   |
                         |   |
                         |   |                         <--- "Slider"
                         |   |
                         |   |
                        ||   ||
                     LOOP|   |LOOP
                        || _ ||
                        ||/ \||
                        ||   ||
                       /||   ||\
                      /         \
                      |         |                      <--- "Ring"	
                      \         /
                       \       /
                        \     /
                         --V--


Feed top of slider through left loop of lower rack (heading northwest)
and continue to slide it so the top goes through the left loop of the
middle rack (heading northeast). At this point the lower rack has
swung about 90 degrees to the west and is perpendicular to the middle rack.

Slide the top of the slider a little further so it goes just to the right
of the post, then over (to the left of) the post, then further left
along the bad of the top rack. At this point it should be free of the
left loop of the middle rack (and to the left of same).

We next move the tip of the slider to the _right_ of this same
left-loop-of-middle-rack (LLOMR). Here's how. Raise the whole slider a little
and twist along the axis of the slider so that the slider is essentially
horizontal; in this way one bar of the slider can crest over part of
that LLOMR. Push the slider forward and it can drop behind the post.
Now move the other bar of the slider under the LLOMR. This should right
the slider so that it is in a vertical plane again rather than horizontal.

Pull the slider down now: it should look like it is resting on the
bottom of the _middle_ rack now (instead of looking like it rests on the
bottom of the _lower_ rack, as in the illustration).

It should be easy to push the slider to the left of the left loop of
the lower rack: as before, roll one bar across the top of the LLOLR and
then the other bar under the bottom of the LLOLR.

Now use the post area in roughly the same way as before: slip the tip
of the slider over the post. Roll one bar of the slider over the LLOMR.
Roll the other bar of the slider under the LLOMR. (Now the slider is 
completely to the left of LLOMR.) Slant the slider so the tip heads
northeast, and push the slider tip over the post. The slider should come free.