一道常見的填字游戲題目，題目如下：

在上面的白色方框內填入適合的單詞，可供選擇的單詞有：dog,run,top,five,four,lost,mess,unit,baker,forum,green,super, prolog, vanish, wonder,yellow。

遵照prolog的原則，只要描述清楚整個問題就可以了，不需要去描述怎么解決問題。試著寫了如下代碼：

    
word(d,o,g). word(r,u,n).
word(t,o,p). word(f,i,v,e).
word(f,o,u,r). word(l,o,s,t).
word(m,e,s,s). word(u,n,i,t).
word(b,a,k,e,r). word(f,o,r,u,m).
word(g,r,e,e,n). word(s,u,p,e,r).
word(p,r,o,l,o,g). word(v,a,n,i,s,h).
word(w,o,n,d,e,r). word(y,e,l,l,o,w).
query:-
    word(L1,L2,L3,L4,L5),
    word(L9,L10,L11,L12,L13,L14),
    word(L1,L6,L9,L15),
    word(L3,L7,L11),
    word(L5,L8,L13,L16),
    writef('word1 is : %w%w%w%w%w\n', [L1, L2, L3, L4, L5]),
    writef('word2 is : %w%w%w%w%w%w\n', [L9,L10,L11,L12,L13,L14]),
    writef('word3 is : %w%w%w%w\n', [L1,L6,L9,L15]),
    writef('word4 is : %w%w%w\n', [L3,L7,L11]),
    writef('word5 is : %w%w%w%w\n', [L5,L8,L13,L16]). 

  

把代碼保存為test.pl文件，命令行鍵入swipl打開swi-prolog的repl。然后加載test.pl文件,加載完畢后鍵入query. 神奇的答案就出來啦~~~。如圖：

用prolog解填字游戲