Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

var (
	dx = []int{0, -1, 0, 1}
	dy = []int{1, 0, -1, 0}
)

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		w, _ := strconv.Atoi(buf[0])
		h, _ := strconv.Atoi(buf[1])
		if w == 0 && h == 0 {
			break
		}
		scanner.Scan()
		buf_ := strings.Split(scanner.Text(), " ")
		xs, _ := strconv.Atoi(buf_[0])
		ys, _ := strconv.Atoi(buf_[1])
		scanner.Scan()
		buf__ := strings.Split(scanner.Text(), " ")
		xg, _ := strconv.Atoi(buf__[0])
		yg, _ := strconv.Atoi(buf__[1])
		xs--
		ys--
		xg--
		yg--
		scanner.Scan()
		n, _ := strconv.Atoi(scanner.Text())
		field := make([][]int, 100)
		for i := range  field {
			field[i] = make([]int, 100)
		}
		visited := make([][]bool, 100)
		for i := range visited {
			visited[i] = make([]bool, 100)
		}
		for i := 0; i < n; i++ {
			scanner.Scan()
			buf___ := strings.Split(scanner.Text(), " ")
			c, _ := strconv.Atoi(buf___[0])
			d, _ := strconv.Atoi(buf___[1])
			x, _ := strconv.Atoi(buf___[2])
			y, _ := strconv.Atoi(buf___[3])
			x--
			y--
			switch d {
			case 0:
				for j := 0; j < 4; j++ {
					for k := 0; k < 2; k++ {
						field[x+j][y+k] = c
					}
				}
			case 1:
				for j := 0; j < 2; j++ {
					for k := 0; k < 4; k++ {
						field[x+j][y+k] = c
					}
				}
			}
		}
		if field[xs][ys] != field[xg][yg] || // スタートとゴールの色が等しくないと"NG"
			field[xs][ys] == 0 { // スタートの色が無職
			fmt.Println("NG")
			continue
		}
		Q := make([]Entry, 0)
		visited[xs][ys] = true
		Q = append(Q, Entry{xs, ys})
		for len(Q) > 0 {
			row := Q[0].x
			col := Q[0].y
			Q = Q[1:]
			for i := 0; i < 4; i++ {
				if 0 <= row+dx[i] && row+dx[i] < w &&
					0 <= col+dy[i] && col+dy[i] < h && // 移動可能な範囲内かどうか
					!visited[row + dx[i]][col + dy[i]] && // 訪問済みか
					field[row+dx[i]][col+dy[i]]==field[row][col] { // 色が同じかどうか
						visited[row+dx[i]][col+dy[i]] = true
						Q = append(Q, Entry{row+dx[i],col+dy[i]})
				}
			}
		}
		if visited[xg][yg] {
			fmt.Println("OK")
		} else {
			fmt.Println("NG")
		}
	}
}

type Entry struct {
	x, y int
}

C++: #include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
typedef pair<int, int> P;

const int INF = (int)1e9;

int board[128][128];

int main()
{
    int w, h;

    while (scanf("%d %d", &w, &h), w){
        int xs, ys;
        int xg, yg;
        scanf("%d %d", &xs, &ys);
        scanf("%d %d", &xg, &yg);

        int n;
        scanf("%d", &n);
        memset(board, 0, 128 * 128);
        while (n-- > 0){
            int c, d, x, y;
            scanf("%d %d %d %d", &c, &d, &x, &y);

            board[y][x] = board[y][x + 1] = c;
            board[y + 1][x] = board[y + 1][x + 1] = c;
            if (d == 0){
                board[y][x + 2] = board[y][x + 3] = c;
                board[y + 1][x + 2] = board[y + 1][x + 3] = c;
            }
            else {
                board[y + 2][x] = board[y + 3][x] = c;
                board[y + 2][x + 1] = board[y + 3][x + 1] = c;
            }
        }

        queue<P> que;
        bool flag = false;
        int color = board[ys][xs];

        if (!color){
            puts("NG");
            continue;
        }

        for (que.push(P(xs, ys)); que.size(); que.pop()){
            P p = que.front();
            int x = p.first;
            int y = p.second;

            if (board[y][x] != color) continue;

            if (x == xg && y == yg){
                flag = true;
                break;
            }
            board[y][x] = !color;
            que.push(P(x + 1, y));
            que.push(P(x - 1, y));
            que.push(P(x, y + 1));
            que.push(P(x, y - 1));
        }

        puts(flag ? "OK" : "NG");
    }

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
using namespace std;



typedef vector<vector<int> > Matrix;
int w,h,xs,ys,xg,yg,n,color;
string res = "NG";

class Block{
public:
  int color;
  int direction;
  int x,y,dx,dy;
  void write(Matrix &board){
    if(direction == 0)
      dx = 4,dy = 2;
    else if(direction == 1)
      dx = 2,dy = 4;
    for(int i=0; i<dx; ++i){
      for(int j=0; j<dy; ++j){
	(board.at(x+i)).at(y+j) = color;
      }
    }
  }
};
  
void func(Matrix &board,int nx,int ny){
  if(board[nx][ny] == 0){
    res = "NG";
    return;
  }
  if( nx==xg && ny==yg){
    res = "OK";
    return;
  }
  board[nx][ny] = 0;
  if( 0<=nx-1 && color==board[nx-1][ny])
    func(board,nx-1,ny);
  if( 0<=ny-1 && color==board[nx][ny-1])
    func(board,nx,ny-1);
  if( nx+1<=w && color==board[nx+1][ny])
    func(board,nx+1,ny);
  if( ny+1<=h && color==board[nx][ny+1])
    func(board,nx,ny+1);
}


int main(void){

  while(1){
    cin >> w >> h;
    if( w==0 && h==0) return 0;
    cin >> xs >> ys >> xg >> yg >> n;
    xs--; ys--; xg--; yg--;
    Block *object[n];
    Matrix board(w, vector<int>(h,0));
    for(int i=0; i<n; ++i){
      object[i] = new Block();
      cin >> object[i]->color;
      cin >> object[i]->direction;
      cin >> object[i]->x;
      cin >> object[i]->y;
      --object[i]->x; --object[i]->y;
      object[i]->write(board);	    
    }
    color = board[xs][ys];
    func(board,xs,ys);
    cout << res << endl;
    delete[] *object;
    board.clear();
  }
  return 0;
}

C++: #include <cstdio>
#include <cctype>
#include <utility>
#include <vector>
#include <queue>
#include <functional>
using namespace std;

#define gcu getchar_unlocked
#define pcu putchar_unlocked
#define _T template <typename T>
#define _HT template <typename H, typename... T>
#define _il inline
#define _in _il int in
#define _sc _il bool scan
_T T in(int c){T n=0;bool m=false;while(isspace(c)){c=gcu();}if(c=='-')m=true,c=gcu();
	do{n=10*n+(c-'0'),c=gcu();}while(c>='0'&&c<='9');return m?-n:n;}
_in() {return in<int>(gcu());}
_T T scan(T &n){int c=gcu();return c==EOF?false:(n=in<T>(c),true);}
_sc(char &c){c=gcu();gcu();return c!=EOF;}
#ifdef _GLIBCXX_STRING
_sc(string &s){int c;s="";
	for(;;){c=gcu();if(c=='\n'||c==' ')return true;else if(c==EOF)return false;s+=c;}}
#endif
_HT _sc(H &h, T&&... t){return scan(h)&&scan(t...);}
#define _vo _il void out
#define _vl _il void outl
_vo(bool b) {pcu('0'+b);}
_vo(const char *s){while(*s)pcu(*s++);}
_vo(char c){pcu(c);}
#ifdef _GLIBCXX_STRING
_vo(string s){for(char c:s)pcu(c);}
#endif
_T _vo(T n){static char buf[20];char *p=buf;
	if(n<0)pcu('-'),n*=-1;if(!n)*p++='0';else while(n)*p++=n%10+'0',n/=10;
	while (p!=buf)pcu(*--p);}
_vl(){out('\n');}
#ifdef _GLIBCXX_VECTOR
_T _vo(vector<T> &v){for(T &x:v)out(&x == &v[0]?"":" "),out(x);outl();}
#endif
_HT _vo(H&& h, T&&... t){out(h);out(move(t)...);}
template <typename... T> _vl(T&&... t){out(move(t)...);outl();}

using V = vector<int>;
using VV = vector<V>;
using P = pair<int, int>;

int main() {
	int dx[] = {4, 2}, dy[] = {2, 4};
	for (int w, h; w = in(), h = in();) {
		P s = {in() - 1, in() - 1}, g = {in() - 1, in() - 1};
		int n = in();
		VV m(h, V(w));
		while (n--) {
			int c = in(), d = in(), x = in() - 1, y = in() - 1;
			for (int i = 0; i < dy[d]; i++)
				for (int j = 0; j < dx[d]; j++)
					m[i + y][j + x] = c;
		}
		function<bool(int, int, int)> f = [&](int x, int y, int c) {
			if (x == g.first && y == g.second)
				return true;
			int dx = 1, dy = 0;
			for (int i = 0; i < 4; i++) {
				int tx = x + dx, ty = y + dy;
				if (tx >= 0 && ty >= 0 && tx < w && ty < h && m[ty][tx] == c) {
					m[ty][tx] = 0;
					if (f(tx, ty, c))
						return true;
				}
				swap(dx, dy *= -1);
			}
			return false;
		};
		int c = m[s.second][s.first];
		m[s.second][s.first] = 0;
		outl(c ? f(s.first, s.second, c) ? "OK" : "NG" : "NG");
	}
}