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>
#define loop(i,a,b) for(int i=a;i<b;i++)
#define rep(i,a) loop(i,0,a)
using namespace std;

int color[200][200];
bool flg[200][200];
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

int w,h,n,c,d,x,y;

void dfs(int ny,int nx,int gy,int gx){
	flg[ny][nx]=true;
	rep(i,4){
		int nex=nx+dx[i];
		int ney=ny+dy[i];
		if(nex>=w || nex<0 || ney>=h || ney<0)continue;
		if(color[ney][nex]==color[ny][nx] && flg[ney][nex]==false)dfs(ney,nex,gy,gx);
	}
	return;
}

int main(){
	pair<int,int> s,g;
	while(1){
		rep(i,200)rep(j,200)color[i][j]=flg[i][j]=0;
		cin>>w>>h;
		if(w==0 && h==0)break;
		cin>>s.first>>s.second;
		cin>>g.first>>g.second;
		cin>>n;
		rep(i,n){
			cin>>c>>d>>x>>y;
			if(d==0){
				rep(j,2){
					rep(k,4){
						color[y-1+j][x-1+k]=c;
					}
				}
			}else{
				rep(j,4){
					rep(k,2){
						color[y-1+j][x-1+k]=c;
					}
				}
			}
		}
		dfs(s.first-1,s.second-1,g.first-1,g.second-1);
		if(flg[g.second-1][g.first-1])cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
	}
	return 0;
}

C++: #include <iostream>

using namespace std;

int w, h;

int field[100][100];
int pathToGoal[100][100];

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

int dfs(int x, int y, int goalX, int goalY, int color) {
    pathToGoal[y][x] = 1;
    if (x == goalX && y == goalY) {
        return 1;
    }
    int res = 0;
    for (int i = 0; i < 4; ++i) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (0 <= nx && nx < w && 0 <= ny && ny < h && pathToGoal[ny][nx] == -1 && field[ny][nx] == color) {
            res += dfs(nx, ny, goalX, goalY, color);
        }
    }
    return res;
}

int main() {
    while (true) {
        cin >> w >> h;
        if (w == 0 && h == 0) {
            return 0;
        }

        for (int i = 0; i < 100; ++i) {
            for (int j = 0; j < 100; ++j) {
                field[i][j] = -1;
                pathToGoal[i][j] = -1;
            }
        }

        int xs, ys;
        int xg, yg;
        int n;
        cin >> xs >> ys;
        cin >> xg >> yg;
        cin >> n;
        xs--;
        ys--;
        xg--;
        yg--;
        for (int i = 0; i < n; ++i) {
            int c, d, x, y;
            cin >> c >> d >> x >> y;
            x--;
            y--;
            if (d == 0) {
                for (int p = 0; p < 2; ++p) {
                    for (int q = 0; q < 4; ++q) {
                        field[y + p][x + q] = c;
                    }
                }
            }
            else {
                for (int p = 0; p < 4; ++p) {
                    for (int q = 0; q < 2; ++q) {
                        field[y + p][x + q] = c;
                    }
                }
            }
        }

        if (dfs(xs, ys, xg, yg, field[xs][ys]) > 0) {
            cout << "OK" << endl;
        }
        else {
            cout << "NG" << endl;
        }
    }
}

C++: #include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
bool N[101][101];
int map[101][101],R,ga,gb,f=0,w,h;
int block(int ,int);
int main()
{
	int i,j,a,n,L,b,c,d,X=0,Y=0,x,y;
	cin>>w>>h;
	while(w!=0||h!=0){
		memset(map,0,sizeof(map));
		memset(N,0,sizeof(N));
		cin>>a>>b;
		cin>>ga>>gb;
		cin>>n;
		for(i=0;i<n;i++){
			cin>>c>>d>>x>>y;
			if(d){
				map[y][x]=c;
				map[y+1][x]=c;
				map[y+2][x]=c;
				map[y+3][x]=c;
				map[y][x+1]=c;
				map[y+1][x+1]=c;
				map[y+2][x+1]=c;
				map[y+3][x+1]=c;

			}
			else{
				map[y][x]=c;
				map[y+1][x+1]=c;
				map[y+1][x+2]=c;
				map[y+1][x+3]=c;
				map[y+1][x]=c;
				map[y][x+1]=c;
				map[y][x+2]=c;
				map[y][x+3]=c;

			}
		}
		R=map[b][a];
		if(R==map[gb][ga]){
			if(block(a,b)) cout<<"OK"<<endl;
		        else cout<<"NG"<<endl;
		}
		else cout<<"NG"<<endl;
		//for(i=0;i<h;i++){
			//for(j=0;j<w;j++){
			//	cout<<map[i][j];
			//}
				
	//		cout<<endl;
		//}
		f=0;
		cin>>w>>h;
	}
	return 0;
}
int block(int b,int a)
{
	//if(f==1) return 1;
	N[b][a]=1;
	if(ga==a&&gb==b) return 1;
	if(a+1!=w){
		if(map[b][a+1]==R&&N[b][a+1]==0) return block(b,a+1);}
	if(b+1!=h){
		if(map[b+1][a]==R&&N[b+1][a]==0) return block(b+1,a);}
	if(a-1!=-1){
		if(map[b][a-1]==R&&N[b][a-1]==0) return block(b,a-1);}
	if(b-1!=-1){
		if(map[b-1][a]==R&&N[b-1][a]==0) return block(b-1,a);}
	return 0;
}

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

using namespace std ;

int map[ 100 ][ 100 ] ;
int w ,h ;
int gx ,gy ;
int way ;

struct ST
{
	int x ;
	int y ;
} ;

ST s ;

void ans()
{
	queue< ST > que ;
	int mx[ 4 ] = { 1 ,0 ,0 ,-1 } ;
	int my[ 4 ] = { 0 ,1 ,-1 ,0 } ;
	bool came[ 100 ][ 100 ] = { false } ;
	que.push( s ) ;
	came[ s.y ][ s.x ] = true ;
	while( ! que.empty() )
	{
		s = que.front() ;
		if( s.x == gx && s.y == gy )
		{
			cout << "OK" << endl ;
			return ;
		}
		que.pop() ;
		for( int i = 0 ; i < 4 ; i++ )
		{
			s.x += mx[ i ] ;
			s.y += my[ i ] ;
			if( came[ s.y ][ s.x ] == false && map[ s.y ][ s.x ] == way )
			{
				came[ s.y ][ s.x ] = true ;
				que.push( s ) ;
				s.x -= mx[ i ] ;
				s.y -= my[ i ] ;
			}
		}
	}
	cout << "NG" << endl ;
	return ;
}


int main()
{
	while( cin >> w >> h ,h )
	{
		int n ;
		int color ,muki ,x ,y ;
		cin >> s.x >> s.y ;
		cin >> gx >> gy ;
		cin >> n ;
		while( n )
		{
			n-- ;
			cin >> color >> muki >> x >> y ;
			x-- ;
			y-- ;
			if( muki )
			{
				for( int i = 0 ; i < 4 ; i++ )
				{
					for( int j = 0 ; j < 2 ; j++ )
					{
						map[ y + i ][ x + j ] = color ;
					}
				}
			}
			else
			{
				for( int i = 0 ; i < 2 ; i++ )
				{
					for( int j = 0 ; j < 4 ; j++ )
					{
						map[ y + i ][ x + j ] = color ;
					}
				}
			}
		}
		gx-- ;
		s.x-- ;
		gy-- ;
		s.y-- ;
		way = map[ s.y ][ s.x ] ;
		if( map[ gy ][ gx ] == way )
		{
			ans() ;
		}
		else
		{
			cout << "NA" << endl ;
		}
	}
	return 0 ;
}