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;
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <functional> //sort(A,A.end(),greater<int>());???????????????
#include <queue>
#include <stack>
#include <vector>

#define INF 10 << 10
#define MP make_pair

int map[124][124];
bool map_flg[124][124];
int x_move[] = { 0,0,1,-1 };
int y_move[] = { -1,1,0,0 };

int main() {
	int w, h;

	while (cin >> w >> h && w != 0 && h != 0) {
		memset(map, 0, sizeof(map));
		memset(map_flg, true, sizeof(map_flg));
		int xs, ys;
		int xg, yg;
		int n;

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

		for (int i = 1; i <= n; ++i) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			int x_, y_;
			if (d == 0) {
				x_ = 4;
				y_ = 2;
			}
			else {
				x_ = 2;
				y_ = 4;
			}
			for (int j = y; j < y + y_; ++j) {
				for (int j2 = x; j2 < x + x_; ++j2) {
					map[j][j2] = c;
				}
			}
		}

		if (map[ys][xs] != map[yg][xg]) {
			cout << "NG" << endl;
			continue;
		}

		stack<pair<int, int> > st;
		st.push(MP(xs, ys));
		int m_c = map[ys][xs];
		bool flg = false;
		while (!st.empty()) {
			int x = st.top().first, y = st.top().second;
			st.pop();
			map_flg[y][x] = false;
			for (int i = 0; i < 4; ++i) {
				int x_ = x + x_move[i], y_ = y + y_move[i];
				if (map[y_][x_] == m_c && map_flg[y_][x_]) {
					if (y_ == yg && x_ == xg) {
						flg = true;
						break;
					}
					st.push(MP(x_, y_));
				}
			}
			if (flg) { break; }
		}

		for (int i = 1; i < h; ++i) {
			for (int i2 = 1; i2 < w; ++i2) {
				cout << map[i][i2];
			}
			cout << endl;
		}

		if (flg) { cout << "OK" << endl; }
		else { cout << "NG" << endl; }
	}

	return 0;
}

C++: #define _USE_MATH_DEFINES
#include<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<stack>
#include<cmath>
#include<climits>
#include<map>
#include<string>
using namespace std;

const int dy[4] = {-1, 0, 1, 0}, dx[4] = {0, 1, 0, -1};

struct Data{
	int y, x;
	Data(){}
	Data(int _y, int _x){
		y = _y; x = _x;
	}
};

int fld[100][100];

void PaintFld(int c, int x, int y, int w, int h){
	for(int i = 0; i < h; i++){
		for(int j = 0; j < w; j++){
			fld[y + i][x + j] = c;
		}
	}
}

int main(){
	int W, H;
	while(cin >> W >> H, W || H){
		fill_n( (int*)fld, 100*100, 0 );
		int Xs, Ys, Xg, Yg, N, C, D, X, Y;
		cin >> Xs >> Ys >> Xg >> Yg >> N;
		Xs--; Ys--; Xg--; Yg--;
		for(int i = 0; i < N; i++){
			cin >> C >> D >> X >> Y;
			X--; Y--;
			if(D == 0) PaintFld(C, X, Y, 4, 2);
			else PaintFld(C, X, Y, 2, 4);
		}

		queue<Data> q;
		Data q_front;
		bool memo[100][100] = {}, ans = false;
		q.push( Data(Xs, Ys) );
		while( !q.empty() ){
			q_front = q.front(); q.pop();

			if(q_front.y == Yg && q_front.x == Xg){
				ans = true; break;
			}

			if(memo[q_front.y][q_front.x]) continue;
			memo[q_front.y][q_front.x] = true;

			for(int i = 0; i < 4; i++){
				int ny = q_front.y + dy[i];
				int nx = q_front.x + dx[i];

				if(ny < 0 || H <= ny || nx < 0 || W <= nx || fld[ny][nx] != fld[Ys][Xs])
					continue;
				q.push( Data(ny, nx) );
			}
		}

		if(ans) puts("OK");
		else puts("NG");
	}
	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();
		int cx = p.second, cy = p.first;

		if (y == gy&&x == gx)break;

		REP(i, 4){
			int nx = cx + dx[i], ny = cy + dy[i];
			if (nx >= 0 && nx < w&&ny >= 0 && ny < h){
				if (table[ny][nx] == table[cy][cx]
					&&dis[ny][nx] == INF){
					dis[ny][nx] = dis[cy][cx] + 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 (dis[gy][gx] != INF)cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}