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 <queue>

using namespace std;

int board[102][102];
bool visited[102][102];

int w, h, xg, yg;

class Point{
public:
	int x, y;

	Point(int xx, int yy){
		x = xx;
		y = yy;
	}
};

const int UNDEFINED = 0;
bool judge(int, int);
int main(void){
	const int BLOCK_WIDTH = 2;
	const int BLOCK_HEIGHT = 4;

	for(int i = 0; i < 102; i ++)
		for(int j = 0; j < 102; j ++){
			board[i][j] = UNDEFINED;
			visited[i][j] = false;
		}	
	for(int xs, ys, n; cin >> w >> h >> xs >> ys >> xg >> yg >> n, w, h;){
		for(int i = 1; i <= w; i ++){
			for(int j = 1; j <= h; j ++){
				board[j][i] = UNDEFINED;
				visited[j][i] = false;
			}
		}

		while(n --){
			int c, d, x, y; cin >> c >> d >> x >> y;
			
			int width = (!d) ? BLOCK_HEIGHT:BLOCK_WIDTH;
			int height = (!d) ? BLOCK_WIDTH:BLOCK_HEIGHT;

			for(int curX = x; curX <= x + width; curX ++)
				for(int curY = y; curY <= y + height; curY ++)
					board[curX][curY] = c;
		}
		cout << ((judge(xs, ys)) ? "OK":"NG") << endl;
	}

	return 0;
}

bool judge(int firstX, int firstY){
	queue<Point> q; Point p(firstX, firstY);
	q.push(p);
	visited[firstY][firstX] = true;

	int targetColor = board[firstY][firstX];
	if(targetColor == UNDEFINED) return false;
	
	while(!q.empty()){
		if(visited[yg][xg]) return true;
		Point currentNode = q.front(); q.pop();

		for(int delta = -1; delta <= 1; delta += 2){
			for(int a = 0; a < 2; a ++){
				Point nextNode(currentNode.x + ((a)?delta:0), currentNode.y + ((a)?0:delta));

				if(!visited[nextNode.y][nextNode.x] && board[nextNode.y][nextNode.x] == targetColor){
					q.push(nextNode);
					visited[nextNode.y][nextNode.x] = true;
				}
			}
		}
	}

	return false;
}

C++: #include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
bool N[102][102];
int map[102][102],R,ga,gb,w,h;
bool 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(b,a)) 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;
		//}
		cin>>w>>h;
	}
	return 0;
}
bool 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 <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>
#include <fstream>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define MOD 1000000007
#define EPS 1e-10
#define MAX_N 100100
#define MAX_M 100100

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;
typedef pair<P, char> PC;
typedef pair<int, string> PSI;

int w, h, sx, sy, gx, gy;
int n, c, d, x, y;

bool ans;

int table[110][110];
int dis[110][110];

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

void solve(){
	REP(i, 110)REP(j, 110)dis[i][j] = INF;
	dis[sy][sx] = 0;

	queue<P> que;
	que.push(P(sy, sx));

	while (que.size()){
		P p = que.front(); que.pop();

		if (p.first == gy&&p.second == gx){
			ans = 1;
			return;
		}
		REP(i, 4){
			int nx = p.second + dx[i], ny = p.first + dy[i];
			if (nx >= 0 && nx < w&&ny >= 0 && ny < h){
				if (table[ny][nx] == table[p.first][p.second]
					&&dis[ny][nx] == INF){
					dis[ny][nx] = dis[p.first][p.second] + 1;
					que.push(P(ny, nx));
				}
			}
		}
	}
}

int main(){
	while (cin >> w >> h&&w + h){
		ans = 0;
		REP(i, 110)REP(j, 110){
			table[i][j] = 0;
		}
		cin >> sx >> sy >> gx >> gy;
		dis[sy][sx] = 1;

		cin >> n;
		REP(i, n){
			cin >> c >> d >> x >> y;
			if (d == 0){
				REP(i, 2){
					REP(j, 4){
						table[y + i][x + j] = c;
					}
				}
			}
			else{
				REP(i, 4){
					REP(j, 2){
						table[y + i][x + j] = c;
					}
				}
			}
		}
		solve();
		if (ans)cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}