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>
#include<algorithm>
using namespace std;
#define MAX_W 100
#define MAX_H 100

int board[MAX_H + 1][MAX_W + 1];
bool ans = false;

void resetBoard();
void setBoard(int c, int d, int x, int y);
void loop(int xn, int yn, int xg, int yg, int c);
void disp(int w, int h);

int main(){
    int w, h;
    while(cin >>w >>h){
        if(w == 0 && h == 0) break;
        int xs, ys, xg, yg, n;
        resetBoard();
        ans = false;
        cin >>xs >>ys >>xg >>yg >>n;
        for(int i = 0; i < n; i++){
            int c, d, x, y;
            cin >>c >>d >>x >>y;
            setBoard(c, d, x, y);
        }
        if(board[ys][xs] == 0){
            cout <<"NG" <<endl;
        } else{
            loop(xs, ys, xg, yg, board[ys + 1][xs + 1]);
            if(ans) cout <<"OK" <<endl;
            else cout <<"NG" <<endl;
        }
    }
    return 0;
}   

void resetBoard(){
    for(int i = 0; i <= MAX_H; i++){
        for(int j = 0; j <= MAX_W; j++){
            board[i][j] = 0;
        }
    }
}

void setBoard(int c, int d, int x, int y){
    int xm[] = {0, 1, 2, 3, 0, 1, 2, 3}, ym[] = {0, 0, 0, 0, 1, 1, 1, 1};
    if(d == 1) swap(xm, ym);
    for(int i = 0; i < sizeof(xm) / sizeof(xm[0]); i++){
        int tmpx = x + xm[i], tmpy = y + ym[i];
        if(tmpx > 0 || tmpy > 0 || tmpx <= MAX_W || tmpy <= MAX_H){
            board[tmpy][tmpx] = c;
        }
    }
}
void loop(int xn, int yn, int xg, int yg, int c){
    if(xn == xg && yn == yg){
        ans = true;
    } else{
        board[yn][xn] = 0;
        int xm[] = {0, 1, 0, -1}, ym[] = {-1, 0, 1, 0};
        for(int i = 0; i < sizeof(xm) / sizeof(xm[0]); i++){
            int tmpx = xn + xm[i], tmpy = yn + ym[i];
            //            cout <<"tmpx = " <<tmpx <<", tmpy = " <<tmpy <<endl;
            if(tmpx > 0 && tmpy > 0 && tmpx <= MAX_W && tmpy <= MAX_H && board[tmpy][tmpx] == c){
                loop(tmpx, tmpy, xg, yg, c);
            }
        }
    }
}

void disp(int w, int h){
    for(int i = 0; i <= h; i++){
        for(int j = 0; j <= w; j++){
            cout <<board[i][j];
        }
        cout <<endl;
    }
}

//0, 00:50:41

C++: #include <bits/stdc++.h>
using namespace std;

int board[101][101];
int xg , yg;
int w, h;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
int sc;
bool b;

void dfs(int x , int y){
	if(x==xg&&y==yg) {b=true;return;}
	for(int i=0;i<4;++i){
		int tx=x+dx[i];
		int ty=y+dy[i];
		if(tx<=0||ty<=0||tx>w||ty>h) continue;
		if(board[tx][ty]!=sc || board[tx][ty]==0) continue;
		if(b) continue;
		dfs(tx,ty);
	}
}

int main(){
	while(cin >> w >> h , w||h){
		int xs , ys;
		int n;
		b=false;
		memset(board,0,sizeof(board));
		cin >> xs >> ys >> xg >> yg >> n;
		for(int i=0;i<n;++i){
			int c , d , x , y;
			cin >> c >> d >> x >> y;
			if(d==0){
				for(int k=0;k<2;++k){
					for(int j=0;j<4;++j){
						board[x+j][y+k]=c;
					}
				}
			} else if(d==1){
				for(int k=0;k<4;++k){
					for(int j=0;j<2;++j){
						board[x+j][y+k]=c;
					}
				}
			}
		}
		sc=board[xs][ys];
		int gc=board[xg][yg];
		if(sc!=gc) {}
		else dfs(xs,ys);
		cout << ( b ? "OK" : "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] == 0 || 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;
	}
   
    /*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;
}

C++: #include<stdio.h>
int w,h;
int is(int x,int y){
	return (x>=0 && x < w && y>=0 && y< h);
}
int main(void){
	const int dx[4]={0,1,0,-1};
	const int dy[4]={1,0,-1,0};
	int qx[100000];
	int qy[100000];
	int p,mx;
    int n,m[101][101]={0};
    int xs,ys,xg,yg,a,c,d,x,y,cnt,f;
	for(;;){
		scanf("%d %d",&w,&h);
		//printf("%d %d\n",w,h);
		if(w==0)break;
		for(int i=0;i<w;i++){
			for(int j=0;j<h;j++){
				m[i][j]=0;
			}
		}
		scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
		scanf("%d",&n);
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			for(int j=0;j<(d==0?2:4);j++){
				for(int k=0;k<(d==0?4:2);k++){
					m[x-1+k][y-1+j]=c;
				}
			}
		}
		c = m[xs-1][ys-1];
		p=0;
		mx=1;
		qx[0]=xs-1;
		qy[0]=ys-1;
		f=1;
/*
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				printf("%d ",m[j][i]);
			}
			puts("");
		}
				printf("%d\n",c);*/
		while(f && p<mx){
			cnt = 0;
			for(int i=0;i<4;i++){
				x = qx[p] + dy[i];
				y = qy[p] + dx[i];
				if(is(x,y) && m[x][y] == c){
					m[x][y]=-1;
					cnt++;
					qx[p+cnt] = x;
					qy[p+cnt] = y;
					if(x == xg-1 && y == yg-1)f=0;
				}
			}
			mx += cnt;
			p++;
		}
		puts(f?"NG":"OK");
	}
    return 0;
}