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 <iostream>
using namespace std;
 
int C[102][102];
int ans;
int xg,yg;
 
void meiro(int W,int H,int c){
  if(W==xg && H==yg){
    ans = 1;
    return;
  }
 
  if(C[W][H]!=c){
    return;
  }
 
  C[W][H] = '.';
 
  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}
 
int main(){
  while(1){
    for(int i=0;i<102;i++){
      for(int j=0;j<102;j++){
        C[i][j] = 0;
      }
    }
     
    int w,h;
    cin >> w >> h;
 
    if(w==0 && h==0){
      break;
    }
 
    int xs,ys;
    cin >> xs >> ys;
 
    cin >> xg >> yg;
 
    int n;
    cin >> n;
    int c[n],d[n],x[n],y[n];
 
    int cbase;
 
    for(int i=0;i<n;i++){
      cin >> c[i] >> d[i] >> x[i] >> y[i];
 
      if(d[i]==0){
        for(int j=x[i];j<x[i]+4;j++){
          for(int k=y[i];k<y[i]+2;k++){
            C[j][k]=c[i];
          }
        }
      }
      if(d[i]==1){
        for(int j=x[i];j<x[i]+2;j++){
          for(int k=y[i];k<y[i]+4;k++){
            C[j][k]=c[i];
          }
        }
      }
 
      if(x[i]==xs &&y[i]==ys){
        cbase = c[i];
      }
    }
    ans = 0;
 if(C[xs][ys] == 0){
      cout << "NG" << endl;
      continue;
    }
    meiro(xs,ys,C[xs][ys]);
   
    if(ans==1){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
 
  return 0;
}

C++: void Eratosthenes(){
	for(int i = 0; i < N; i++){
		arr[i] = 1;
	}
	for(int i = 2; i < sqrt(N); i++){
		if(arr[i]){
			for(int j = 0; i * (j + 2) < N; j++){
				arr[i *(j + 2)] = 0;
			}
		}
	}

	for(int i = 2; i < N; i++){
		if(arr[i]){
			//cout << i << endl;
		}
	}
}

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

int map[102][102];
int nx, ny;

void route(int h, int w, int color) {
	if (map[h][w] != color)
		return;
	map[h][w] = 0;
	route(h, w + 1, color);
	route(h + 1, w, color);
	route(h, w - 1, color);
	route(h - 1, w, color);
}


int main() {
	int h, w, xs, ys, xg, yg, n;

	while (1) {
		cin >> h >> w >> xs >> ys >> xg >> yg >> n;
		if (h == 0 && w == 0)
			break;

		int c, d, x, y;
		for (int i = 0; i<n; i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				for (int j = 1; j <= 4; j++)
					map[j + x][y] = map[j + x][y+1] = c;
			}
			else {
				for (int j = 1; j <= 4; j++)
					map[x][y + j] = map[x + 1][y+j] = c;
			}
		}
		int color = map[xs][ys];
		route(xs, ys, color);
		if (xg == 0 && yg == 0)
			cout << "OK" << endl;
		else
			cout << "NG";
		cout << nx << ' ' << ny << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<utility>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<complex>
#define INF 2147483647
#define llINF 9223372036854775807
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long

using namespace std;
int main(){
  int w,h;
  while(cin>>w>>h,w+h){
    int xs,ys,xg,yg;
    bool Map[h+10][w+10]={};
    bool flag=false;
    cin>>xs>>ys>>xg>>yg;
    int n;cin>>n;
    int Map2[h+10][w+10]={};
    Map[ys][xs]=true;
    queue<pair<int,int> >que;
    que.push(mp(ys,xs));
    for(int i=0;i<n;i++){
      int c,d,x,y;
      cin>>c>>d>>x>>y;
      if(d==0){
	for(int i=y;i<y+2;i++)
	  for(int j=x;j<x+4;j++)
	    Map2[i][j]=c;
      }else if(d==1){
	for(int i=y;i<y+4;i++)
	  for(int j=x;j<x+2;j++)
	    Map2[i][j]=c;
      }
    }
    int vx[4]={0,-1,0,1};
    int vy[4]={1,0,-1,0};
    while(!que.empty()){
      pair<int,int>now=que.front();
      que.pop();
      if(now.F==xg&&now.S==yg){
	flag=true;
	break;
      }
      for(int kk=0;kk<4;kk++){
	int as=now.F+vx[kk];int bs=now.S+vy[kk];
	if(as<h&&as>=0&&bs<w&&bs>=0&&Map2[now.F][now.S]==Map2[as][bs]&&!Map[as][bs]){
	  que.push(mp(as,bs));
	  Map[as][bs]=true;
	}
      }
    }
    if(flag)
      cout<<"OK"<<endl;
    else
      cout<<"NG"<<endl;
  }
  return 0;
}

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

int F[102][102];

void
DFS (int Y, int X, int A)
{
  if (F[Y][X] != A)
    return;

  F[Y][X] = 7;

  DFS (Y - 1, X, A);
  DFS (Y, X + 1, A);
  DFS (Y + 1, X, A);
  DFS (Y, X - 1, A);
}

int
main ()
{
  int w, h;
  int xs, ys;
  int xg, yg;
  int n;
  int c, d, x, y;

  while (true)
    {
      cin >> w >> h;
      if (w == 0 && h == 0)
	break;
      cin >> xs >> ys;
      cin >> xg >> yg;
      cin >> n;

      for (int i = 0; i < n; i++)
	{
	  cin >> c >> d >> x >> y;
	  if (d == 0)
	    {
	      for (int a = 0; a < 4; a++)
		{
		  for (int b = 0; b < 2; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}

	    }
	  else
	    {
	      for (int a = 0; a < 2; a++)
		{
		  for (int b = 0; b < 4; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}
	    }

	}


      if (F[ys][xs] == 1 || F[ys][xs] == 2 || F[ys][xs] == 3
	  || F[ys][xs] == 4 || F[ys][xs] == 5)
	{
	  DFS (ys, xs, F[ys][xs]);
	}

      if (F[yg][xg] == 7)
	{
	  cout << "OK" << endl;
	}
      else
	{
	  cout << "NG" << endl;
	}
   
    /*for (int y = 0; y < h; y++)
	{
	  for (int x = 0; x < w; x++)
	    {
	      cout << F[y][x];
	    }
         cout << endl;
	}*/
   
    for (int y = 1; y <= h; y++)
	{
	  for (int x = 1; x <= w; x++)
	    {
	      F[y][x] = 0;
	    }
	}

    
   
    }

  return 0;
}