Giant Pyramid - a very difficult puzzle.

> I have a version of this puzzle.  I purchased it about 3 years ago,
> disassembled it without paying much attention and have not been able to
> reassemble it yet (of course I have not been trying continuously).  On
> the base, is a label with this info:
> 
> Giant Pyramid - a very difficult puzzle.
> Item No 186.
> Gordon Brothers
> P.O. Box 4614
> Chico, CA 95927
> 
> Here's what the pieces look like:
> 
> There are 9 pieces of equal sized attached spheres.
> Each will lie flat, that is, all the pieces are "planar".
> They assemble into a tetrahedral shape with an edge of 5 spheres.
> 
>     4 of these. The angle is 90 deg.
> 
>     O O O
>         O
> 
>     And 1 each of these. All angles are 60 deg.
> 
>      O O     O O O     O O O    O O      O O O
>     O   O       O                  O O        O

SPOILER

Numbers:
        20       22        10       21       23        30-33

       O O     O O O     O O O    O O      O O O       O O O
      O   O       O                  O O        O      O

  .  .  .  . 20
  .  .  . 20  .
  .  . 22  .  .
  . 22  .  .  .
 22  .  .  .  .

  .  .  . 31  .
  .  . 31  . 31
  . 31  . 20  .
 22  . 30  .  .
  . 21  .  .  .

  .  . 33  .  .
  . 33  . 33  .
 33  . 21  . 20
  . 21  . 30  .
  .  . 10  .  .

  . 32  .  .  .
 32  . 21  .  .
  . 32  . 23  .
  .  . 32  . 30
  .  .  . 10  .

 23  .  .  .  .
  . 23  .  .  .
  .  . 23  .  .
  .  .  . 30  .
  .  .  .  . 10