_|_
                / \
               /_ _\
               /   \
              /     \
             A       B
            /_________\
             /   C   D
            /         \
           / E   F     \
          /             \
         /___G_______H___\
                | |
                | |

A, B, C, D, E, F, G & H are presents on a Christmas tree in the same spatial position. Each is addressed from one of eight different people to one of the others and is wrapped in paper and ribbon of two different colours, including white. Can you tell from and to whom each parcel is addressed and work out the colour of its paper and decorative ribbon?

1) The parcel that Nicholas is giving to Duane is horizontally level with ( and further right than, as per the arrangement ) the one wrapped in red paper. The ribbon Nicholas has used is of the same colour as the paper on the parcel decorated with lilac ribbon.
2) The parcel tied with green ribbon is from the person to whom Lucy is giving something. The gift Lucy will receive is not from anyone to whom Caroline or Babs have addressed their parcels.
3) The parcel addressed to Margaret has green paper. It is directly above the one with silver ribbon; and its ribbon is of the same colour as the paper used to wrap parcel H.
4) Parcel E has red ribbon and is addressed to the person who is giving something to Pete.
5) Parcel G has silver paper and is adorned with ribbon of the same colour as the paper on Parcel A.
6) The parcel with lilac paper ( but not green ribbon ) is from Babs and has a ribbon of the same colour as the paper on the parcel that is horizontally level with one from Caroline.
7) The parcel with blue paper has ribbon of same colour as the paper on the parcel addressed to Quentin.
8) The parcel that Margaret has wrapped is for the person who is giving the parcel tied with silver ribbon. The parcel from Margaret is one level lower than the gift tied with pink ribbon and the paper Margaret has used is the same colour as the ribbon on present C.
9) The package tied with gold ribbon is in the same vertical line as (and is higher than) the one tied with blue ribbon, which is for Caroline ( but not from the person to whom Caroline has addressed her present ).

I believe the author meant to imply these assumptions.  With them,
I was able to solve the puzzle in a reasonably straightforward
(though long and difficult) way, so if I didn't make a mistake,
then with these assumptions added there is a unique
solution.   I haven't actually proven that
these assumptions are required to make the solution unique.

-- Each of the eight people received exactly one of the eight parcels.
-- No two parcels had the same colour of paper.
-- No two parcels had the same colour of ribbon.
-- The set of eight colours of the paper is the same set [though in a different order] as the set of eight colours of the ribbons.
-- "Directly above" implies "without another parcel between the two".

Posted by Catherine Woodgold on 2006-09-28 15:43:08