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 dx[] = {0,1,0,-1},dy[] = {1,0,-1,0};

int w,h,xs,ys,xg,yg,n,cc;
int field[100][100];
bool flag;

void dfs(int x,int y,int c){
	if(flag) return;
	if(x == xg && y == yg) {
		flag = true;
		return;
	}
	for(int i = 0;i < 4;i++){
		int nx = x + dx[i],ny = y + dy[i];
		if(nx >= 0 && nx < w && ny >= 0 && ny < h && field[nx][ny] == c){
			field[nx][ny] = 0;
			dfs(nx,ny,c);
		}
	}
}

int main(){
	while(1){
		flag = false;
		cin >> w >> h;
		if(!w) break;
		for(int i = 0;i < w;i++){
			for(int j = 0;j < h;j++) field[i][j] = 0;
		}
		cin >> xs >> ys >> xg >> yg >> n; xs--;ys--;xg--;yg--;
		for(int i = 0;i < n;i++){
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			if(d == 1){
				for(int k = 0;k < 2;k++){
					for(int j = 0;j < 4;j++) field[x + k - 1][y + j - 1] = c;
				}
			}else{
				for(int k = 0;k < 4;k++){
					for(int j = 0;j < 2;j++) field[x + k - 1][y + j - 1] = c;
				}
			}
		}
		if(field[xs][ys] == 0){
			cout << "NG" << endl;
			continue;
		}
		cc = field[xs][ys];
		field[xs][ys] = 0;
		dfs(xs,ys,cc);
		if(flag) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<iostream>

using namespace std ;

int mx[] = { 1 ,0 ,0 ,-1 } ;
int my[] = { 0 ,1 ,-1 ,0 } ;

int w ,h ;
int gx ,gy ;

int ok_or_ng( int x ,int y ,bool came[][ 110 ] )
{
	came[ y ][ x ] = false ;

	if( x == gx && y == gy )
		return 1 ;

	for( int i = 0 ; i < 4 ; i++ )
	{
		int xx = x + mx[ i ] ;
		int yy = y + my[ i ] ;
		if( xx > 0 && xx <= w && yy > 0 && yy <= h && came[ yy ][ xx ] )
		{
			came[ yy ][ xx ] = false ;
			return ok_or_ng( xx ,yy ,came ) ;
		}
	}
	return 0 ;
}

void wide( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 2 ; i++ )
	{
		for( int j = 0 ; j < 4 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

void high( int x ,int y ,int c ,int map[][ 110 ] )
{

	for( int i = 0 ; i < 4 ; i++ )
	{
		for( int j = 0 ; j < 2 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

int main()
{
	while( cin >> w >> h )
	{
		if( w == h && w == 0 )
		return 0 ;
		bool came[ 110 ][ 110 ] = { false } ;
		int map[ 110 ][ 110 ] = { 0 } ;

		int sx ,sy ;

		cin >> sx >> sy ;
		cin >> gx >> gy ;

		int n ;
		cin >> n ;					// 0 w	1 h

		int c ,d ,x, y ;
		for( int i = 0 ; i < n ; i++ )
		{
			cin >> c >> d >> x >> y ;
			d ? high( x ,y ,c ,map ) : wide( x ,y ,c ,map ) ;
		}

		c = map[ gy ][ gx ] ;

		came[ gy ][ gx ] = false ;	//

		for( int i = 1 ; i <= h ; i++ )
		{
			for( int j = 1 ; j <= w ; j++ )
			{
				if( map[ i ][ j ] == c )
					came[ i ][ j ] = true ;
			}
		}

		ok_or_ng( sx ,sy ,came ) ? printf( "OK\n" ) : printf( "NG\n" ) ;
	}
}

C++: 
//インクルード文
#include <iostream>
#include <stack>
#include <vector>
#include <stdlib.h>
#include <cstdio>
#include <string>
//#include <assert.h>

//:std省略
using namespace std;

//グローバル変数
int f[1000][1000];

//マクロ指定
#define fc f[x + j][y + l] = c

//深さ優先探索( dfs = Depth - First Search )
void dfs(int a, int b, int c) {

	if (f[a][b] == c) {


		f[a][b] = 10;
		dfs(a + 1, b, c);
		dfs(a - 1, b, c);
		dfs(a, b + 1, c);
		dfs(a, b - 1, c);


	}

//	else return;

}

//メイン文
int main(){

	int w=0, h=0, n = 0;
	int i, j, l;
	int xs, ys; 
	int xg, yg;

	

	for (;;) {
		cin >> w >> h;

		const int cnt = w + h;
		
		if ( cnt == 0) break;
		
		for (i = 1; i <= h; ++i) {
			for (j = 1; j <= w; ++j) {
				f[i][j] = -1;
			}
		}

		cin >> xs >> ys;
		cin >> xg >> yg;
		cin >> n;

		for (i = 0; i < n; ++i) {
			int c, d, x, y;

			cin >> c >> d;
			cin >> x >> y;

			if (d == 0) {
				for (j = 0; j < 4; ++j) {
					for (l = 0; l < 2; ++l) {
						fc;
					}
				}
			}

			else {//d==1

				

				for (j = 0; j < 2; ++j) {
					for (l= 0; l < 4; ++l) {
						fc;
					}
				}
			}
		}
/*

			if (d == 0) {
				for (j = 0; j < 2; ++j) {
					for (l = 0; l < 4; ++l) {
						f[x + j][y + l] = c;
					}
				}
			}

			else {
				for (j = 0; j < 4; ++j) {
					for (l= 0; l < 2; ++l) {
						f[x + j][y + l] = c;
					}
				}
			}	
		}

*/


		dfs(xs, ys, f[xs][ys]);


//		char gg = 'OK';
//		char ggwp = 'NG';


		

		if (f[xg][yg] == 10) printf("OK\n");

		else 		         printf("NG\n");



			//			assert(i == 10);
			//			assert(i = 9);
			//			assert(i = 8);
			//			assert(i = 7);
			//			assert(i = 6);
			//			assert(i = 5);
			//			assert(i = 4);
			//			assert(i = 3);
			//			assert(i = 2);
			//			assert(i = 1);

		


	}
	return 0;
}

/*


20 20
1 1
9 9
7
2 0 1 1
5 1 1 3
2 1 3 3
1 1 5 2
5 1 7 3
2 0 2 7
2 0 6 8
20 20
9 9
1 1
6
2 0 1 1
1 0 5 1
2 1 1 3
5 0 1 7
3 1 5 5
4 1 8 5
0 0


*/

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


#define rep(i,n) for(short i = 0; i < n; i++)
#define MAX 50

int dx[] = {0,0,-1,1},
	dy[] = {1,-1,0,0};

typedef pair<short,short> P;
P S,G;
short w,h;

short color;
	queue<P> que;
	
bool check(short maze[MAX][MAX])
{
	que.push(S);

	color = maze[S.second][S.first];

	short nx,ny;
	while(que.size()){
		P p = que.front();	que.pop();

		if(p == G){
			while(que.size())
				que.pop();
			return true;
		}

		rep(i,4){
			nx = p.first + dx[i], ny = p.second + dy[i];
			
			if(nx > -1 && ny > -1 && nx < w && ny < h &&
				maze[ny][nx] == color){
					maze[ny][nx] = -1;
					que.push(P(nx,ny));
			}

		}
	}


	
	return false;
}

int main(void)
{
	short n,c,d,x,y;
	short maze[MAX][MAX];
	while(cin >> w >> h, w){
		rep(i,MAX)
			rep(j,MAX)
			maze[i][j] = -10;
		cin >> S.first >> S.second;
		cin >> G.first >> G.second;
		S.first = S.first / 2;
		S.second= S.second/ 2;

		cin >> n;

		rep(i,n){
			cin >> c >> d >> x >> y;
			x /= 2;
			y /= 2;
			x++;
			y++;

			if(d == 0)
				maze[y][x] = maze[y][x+1] = c;
			else
				maze[y][x] = maze[y+1][x] = c;
		}
		
		if(maze[S.second][S.first] != -10 && maze[S.second][S.first] == maze[G.second][G.first] && check(maze))
			cout << "OK\n";
		else
			cout << "NG\n";

	}
	
	return 0;
}