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 <bits/stdc++.h>
#include<stdio.h>
using namespace std;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) begin(a),end(a)
#define MS(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(10)
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;
const ll INF = 114514810;
const ll MOD = 1000000007;
const double EPS = 1e-8;
const double PI = acos(-1.0);
struct edge
{
	int from, to, cost;
	bool operator < (const edge& e) const { return cost < e.cost; }
	bool operator >(const edge& e) const { return cost > e.cost; }
};
int dx[] = { -1, 0, 0, 1 }; int dy[] = { 0, -1, 1, 0 };
bool valid(int x, int y, int h, int w) { return (x >= 0 && y >= 0 && x < h&&y < w); }
///*************************************************************************************///
///*************************************************************************************///
///*************************************************************************************///


int main()
{
	int w, h;
	while (cin >> w >> h, w)
	{
		int fld[100][100] = {};
		int sx, sy, gx, gy, n;
		cin >> sy >> sx >> gy >> gx >> n;
		sy--; sx--; gy--; gx--;
		while (n--)
		{
			int c, d, x, y;
			cin >> c >> d >> y >> x;
			y--; x--;
			if (d)
			{
				REP(i, 4)REP(j, 2) fld[x + i][y + j] = c;
			}
			else
			{
				REP(i, 2)REP(j, 4) fld[x + i][y + j] = c;
			}
		}
		/*
		REP(i, h)
		{
			REP(j, w) cout << fld[i][j];
			cout << endl;
		}
		*/
		queue<P> que;
		que.push(P(sx, sy));
		bool f = false;
		int color = fld[sx][sy];
		while (que.size())
		{
			if (color == 0) break;
			int tx = que.front().first, ty = que.front().second;
			fld[tx][ty] = 0;
			que.pop();
			if (tx == gx&&ty == gy)
			{
				f = true;
				break;
			}
			REP(i, 4)
			{
				int nx = tx + dx[i], ny = ty + dy[i];
				if (valid(nx, ny, h, w) && fld[nx][ny] == color) que.push(P(nx, ny));
			}
		}
		puts(f ? "OK" : "NG");
	}
	return 0;
}

C++: #include<iostream>
#include<cstring>
#include<queue>
#include<map>
using namespace std;
int C,goal,n,x,y,xs,ys,xg,yg,mas[110][110]={{0}};
int dx[4]={0,0,1,1};
int dy[4]={0,1,0,1};
int d[110][110];
typedef pair<int,int>P;

int bfs();
int main(){

  while(1){
    goal=0;
    memset(mas,0,sizeof(mas));
    cin >> x >> y;//ボードの大きさ。 ※：x=横。y=縦。
    if(x==0 && y==0){
      break;
    }
    cin >> xs >> ys;//スタート地点。
    cin >> xg >> yg;//ゴール地点。
    cin >> n;//ブロックの数。
    
    //色染め。
    int color,dire,xx,yy;
    for(int t=0;t<n;t++){
      cin >> color >> dire >> xx >> yy;
      if(dire==0){
	for(int i=0;i<2;i++){
	  for(int j=0;j<4;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
      else{
	for(int i=0;i<4;i++){
	  for(int j=0;j<2;j++){
	    mas[yy+i][xx+j]=color;
	  }
	}
      }
      
    }
    
    //通る色　摘出。
    C=mas[1][1];
    
    bfs();
    
    if(goal==1){
      cout << "OK" << endl;
    }
    else{
      cout << "NG" << endl;
    }
    
  }
}

int bfs(){
  queue<P>que;
  memset(d,-1,sizeof(d));
  que.push(P(ys,xs));
  d[ys][xs]=0;
  while(!que.empty()){
    P p=que.front();
    que.pop();
    if(p.first==yg && p.second==xg){
      goal=1;
      break;
    }
    for(int i=0;i<4;i++){
      int ny=p.first+dy[i];
      int nx=p.second+dx[i];
      if(mas[ny][nx]==C && ny>=1 && ny<=y && nx>=1 && nx<=x && d[ny][nx]==-1){
	que.push(P(ny,nx));
	d[ny][nx]=0;
      }
    }
  }
  return (0);
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int w,h,xs,ys,xg,yg,n;
int c,d,x,y,ans=0,f=0;
int map[101][101]={0},v[101][101]={0};
int root(int x,int y,int vmap[][101]){
	int mx[]={0,1,0,-1},fx;
	int my[]={1,0,-1,0},fy;
	if(x==xg&&y==yg){
		f=1;
		return f;
	}
	for(int i=0;i<4;i++){
		fx=x+mx[i];
		fy=y+my[i];
		if(map[fy][fx]==map[xs][ys]&&fy>=0&&fy<h&&fx>=0&&fx<w&&vmap[fy][fx]==0){
			vmap[fy][fx]=1;
			return root(fx,fy,vmap);
		}
	}
	return f;
}
int main(){
	scanf("%d %d",&w ,&h);
	while(w!=0&&h!=0){
		scanf("%d %d %d %d %d",&xs ,&ys ,&xg ,&yg ,&n);
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c ,&d ,&x ,&y);
			if(d==0){
				for(int w=x;w<x+4;w++){
					for(int h=y;h<y+2;h++){
						map[h][w]=c;
					}
				}
			}
			if(d==1){
				for(int w=x;w<x+2;w++){
					for(int h=y;h<y+4;h++){
						map[h][w]=c;
					}
				}
			}
		}
		/*for(int i=0;i<w;i++){
			for(int i1=0;i1<h;i1++){
				printf("%d ",map[i][i1]);
			}printf("\n");
		}*/
		x=xs;
		y=ys;
		ans=root(x,y,v);
		if(ans==1){
			printf("OK\n");
		}
		else{
			printf("NG\n");
		}
		for(int i=0;i<101;i++){
			for(int i1=0;i1<101;i1++){
				map[i][i1]=0;
				v[i][i1]=0;
			}
		}
		f=0;
		ans=0;
		scanf("%d %d",&w ,&h);
	}
	return 0;
}