DouKaku?

import std.stdio;
import std.file;
import std.string;
import std.utf;

void main(){
    wchar[][][wchar] hash;
    foreach(word; splitlines(cast(string)read("words.txt"))){
        wchar[] convedWord = word.toUTF16();
        hash[convedWord[0]] ~= convedWord;
    }
    bool[wchar[]] checked;
    int count;
    foreach(arr; hash){
        foreach(top; arr){
            if(top[0] in hash){
                foreach(left; hash[top[0]]){
                    if(!(left in checked) && top[3] in hash){
                        foreach(right; hash[top[3]]){
                            if(left[3] in hash && right != top && right != left){
                                foreach(bottom; hash[left[3]]){
                                    if(bottom[3] == right[3] && bottom[0] != top[3]
                                       && bottom != top && bottom != left && bottom != right){
                                        writefln(top);
                                        writefln(left[1], "　　", right[1]);
                                        writefln(left[2], "　　", right[2]);
                                        writefln(bottom);
                                        writefln("-------");
                                        count++;
                                    }
                                }
                            }
                        }
                    }
                }
            }
            checked[top] = true;
        }
    }
    writefln(count);
}