%                   NOVEL ARRANGEMENT
%
%	Logic Problems, Issue 10, page 51
% 
% A man who owned a lot of books, but read very few, acquired a new bookcase, 
% on the four shelves of which he decided to put the novels of sixteen authors,
% four to each shelf. Each author was allotted exactly the same space, so that
% the more prolific ones were represented by a sample of their novels. From the
% information given below, discover which space, as numbered on the diagram,
% he allocated to each author.
% 
%
% 1. Hemingway and Hardy were on the extreme left of their rows.
%
%
% 2. The works of Virginia Woolf were as far removed as possible from those
%    of D H Lawrence. (Hint: diagonally opposite corners)
%
%
% 3. Graham Greene was directly flanked horizontally by Jane Austen and Arnold
%    Bennett and vertically by Mrs Gaskell and Trollope.
%
%
% 4. Dickens was to the immediate left of R L Stevenson.
%
%
% 5. Scott had Mark Twain immediately above him and Iris Murdoch immediately
%    below. Jane Austen was in the same vertical column as Thackeray, but on
%    a higher shelf.
%
%
% 6. With the two American novelists, one appears on shelf 1 and the other on shelf 3 
%
%
% 7. None of the four women novelists appeared on the top shelf.
%
%
% 8. When all the named authors have been fitted into their spaces, there
%    will be one space left for Lawrence Durrell.
%
% 
%                     +-------------------+
%            shelf 1  |  1 |  2 |  3 |  4 |
%                     |----|----|----|----|
%            shelf 2  |  5 |  6 |  7 |  8 |
%                     |----|----|----|----|
%            shelf 3  |  9 | 10 | 11 | 12 |
%                     |----|----|----|----|
%            shelf 4  | 13 | 14 | 15 | 16 |
%                     +-------------------+
% 
% 
% 
male(hemingway).
male(hardy).
male(d_h_lawrence).
male(scott).
male(mark_twain).
male(graham_greene).
male(arnold_bennett).
male(lawrence_durrell).
male(r_l_steveson).
male(trollope).
male(thackeray).
male(dickens).
%
female(virginia_woolf).
female(jane_austen).
female(iris_murdoch).
female(mrs_gaskell).
%
diag_opp(1, 16).
diag_opp(4, 13).
%
american(mark_twain).
american(hemingway).
%