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>
int s,t,u,v,n,c,d,x,y,i,j,f[102][102],a[4]={1,0,-1,0};int rec(int x,int y){if(f[x][y]==c)for(int i=4;i-->0;f[x][y]=9)rec(x+a[i],y+a[(i+3)%4]);}main(){for(;std::cin>>x>>y>>s>>t>>u>>v>>n,x;puts(f[u][v]-9?"NG":"OK")){for(j=0;j++<101;)for(i=0;i++<101;)f[i][j]=0;for(;n-->0;c=f[s][t]){std::cin>>c>>d>>x>>y;for(i=2;d&i-->0;)for(j=4;j-->0;)f[x+i][y+j]=c;for(i=4;!d&i-->0;)for(j=2;j-->0;)f[x+i][y+j]=c;}c&&rec(s,t);}}

C++: #include<iostream>
using namespace std;
int w, h, xs, ys, xg, yg, stage[101][101];
int ny[4] = { 0, 1, 0, -1 }, nx[4] = { 1, 0, -1, 0 };
int bc;
bool ans = false;
void func(int x, int y, int lastp){
	if (x == xg && y == yg){
		ans = true;
	}
	for (int i = 0; i < 4; i++){
		if (stage[y + ny[i]][x + nx[i]] != bc || i == lastp) return;
		func(x + nx[i], y + ny[i], (i + 2) % 4);
	}
}
int main(){
	int n, c, d, x, y, bw, bh;
	while (1){
		for (int i = 0; i < 101; i++){
			for (int j = 0; j < 101; j++){
				stage[i][j] = 0;
			}
		}
		cin >> w >> h;
		if (w == 0 && h == 0) return 0;
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 0; i < n; i++){
			cin >> c >> d >> x >> y;
			if (d == 0){
				bw = 4;
				bh = 2;
			}
			else{
				bw = 2;
				bh = 4;
			}
			for (int j = 0; j < bh; j++){
				for (int k = 0; k < bw; k++){
					stage[y + j][x + k] = c;
				}
			}
		}
		bc = stage[ys][xs];
		if (bc == 0){
			cout << "NG\n";
			return 0;
		}
		func(1, 1, -1);
		if (ans == true) cout << "OK\n";
		else cout << "NG\n";
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int w,h,xs,ys,xg,yg,n;
int c,d,x,y,ans,f=0;
int map[100][100],v[100][100]={0};
int root(int x,int y,int vmap[][100]){
	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 0;
}
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;
					}
				}
			}
		}
		x=xs;
		y=ys;
		ans=root(x,y,v);
		if(ans==1){
			printf("OK\n");
		}
		else{
			printf("NG\n");
		}
		scanf("%d %d",&w ,&h);
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
   
int F[102][102];
int xg,yg,w,h;
   
   
void DFS(int Y,int X,int c){
  //if(Y < 1 || X < 1)
    //return;
  if(F[Y][X] != c){
    return;
  }
   
  F[Y][X] = -1;
  DFS(Y+1,X  ,c);
  DFS(Y-1  ,X,c);
  DFS(Y,X+1  ,c);
  DFS(Y  ,X-1,c);
}
   
   
int main(){
  int xs,ys,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;
for(int i=0; i<102; i++){
      for(int j=0; j<102; j++){
        F[i][j] = 10;
      }
    }
       F[0][-1] = 0;
    cin >> xs >> ys >> xg >> yg >> n;
   
   
    for(int i=0;i<n;i++){
      int c,d,x,y;
      cin >> c >> d >> x >> y;
      if(c == 0)
         c = 1919810;
      if(d == 0){
        for(int j=0;j<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }
  DFS(xs,ys,F[xs][ys]);
   
  if(F[xg][yg] == -1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}

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] == F[ys][xs])
	{
	  cout << "OK" << endl;
	}
      else
	{
	  cout << "NG" << endl;
	}


    }

  return 0;
}