Annotating Don.Woods diagram  (which is in the correct orientation)
              2       3
        ---------------------
        |     @       #     |
        |     @       #     |
      1 |$$    @      # %%%%| 4
        |  $    @    %#%    |
        |   $    @ %% #     |
        |    $    %@  #     |
        |    $  %%  @@#     |
        |    %%%      #@@   |
      4 |%%%% $       #  @@@| 2
        |     $       #     |
        |     $       #     |
        ---------------------
              1        3

The duplicate piece in each tangle is:
                1       2       3       4
Tangle 1        Blue    Red     Yellow  Green
Tangle 2        Yellow  Blue    Green   Red
Tangle 3        Green   Yellow  Blue    Red
Tangle 4        Red     Green   Yellow  Blue

All 4 Tangles are the same puzzle, just colored differently.
Each has all 24 color permutations, plus a duplicate.

Each Tile also has a letter (A-Y) on the back, and a reference to the
Tangle that it occurs in. These letters appear to be for reference
only. I have found no corresponddence between the letterings in one
puzzle, and the letterings in another. I just use them as a convenience
for recording configurations, and sorting through the tiles.

------
ccw@eql.caltech.edu (Chris Worrell)