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<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<climits>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define reg(i,a,b) for(int i=(a);i<=(b);i++)
#define irep(i,n) for(int i=((int)(n))-1;i>=0;i--)
#define ireg(i,a,b) for(int i=(b);i>=(a);i--)
typedef long long int lli;
typedef pair<int,int> mp;
#define fir first
#define sec second
#define IINF INT_MAX
#define LINF LLONG_MAX


int map[150][150]={};
int gone[150][150]={};

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

bool dfs(int nx,int ny){
	if(gone[nx][ny])return false;
	gone[nx][ny]=1;
	if(nx == gx && ny == gy)return true;
	bool res = false;
	rep(i,4){
		int tx = nx+dx[i],ty=ny+dy[i];
		if(map[tx][ty]!=map[nx][ny])continue;
		res |= dfs(tx,ty);
	}
	return res;
}

int main(void){
	while(1){
		int w,h;
		scanf("%d%d",&w,&h);
		if(w==0 && h==0)break;
		int sx,sy,n;
		scanf("%d%d%d%d%d",&sx,&sy,&gx,&gy,&n);
		memset(map,0,sizeof(map));
		memset(gone,0,sizeof(gone));
		rep(i,n){
			int c,d,nx,ny;
			scanf("%d%d%d%d",&c,&d,&nx,&ny);
			int fx=2,fy=4;
			if(d==0)swap(fx,fy);
			rep(x,fx)rep(y,fy){
				map[x+nx][y+ny]=c;
			}
		}
		/*
		rep(y,20)rep(x,20){
			printf("%d%c",map[x][y],x==19?'\n':' ');
		}*/
		if(dfs(sx,sy))printf("OK\n");
		else printf("NG\n");
	}
		
	return 0;
}

C++: #include<stdio.h>
#include<algorithm>
#include<functional>
int w,h;
int xs,ys,xg,yg;
int n;
int c,d,x,y;
int map[101][101];
int flg=0,temp;
void func(int ,int);
using namespace std;
int main(void){
	while(1){
		scanf("%d %d",&w,&h);
		if(w==0 && h==0){
			break;
		}
		int i,j,k;
		for(i=1;i<=100;i++){
			for(j=1;j<=100;j++){
				map[i][j]=0;
			}
		}
		scanf("%d %d %d %d %d",&xs,&ys,&xg,&yg,&n);
		for(i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			if(d==0){
				for(k=0;k<=1;k++){
					for(j=0;j<=3;j++){
						map[y+k][x+j]=c;
					}
				}
			}
			if(d==1){
				for(k=0;k<=3;k++){
					for(j=0;j<=1;j++){
						map[y+k][x+j]=c;
					}
				}
			}
			/*for(j=1;j<=10;j++){
				for(k=1;k<=10;k++){
					printf("%d ",map[j][k]);
				}
				printf("\n");
			}
			printf("\n");*/
		}
		flg=0;
		if(map[ys][xs]==map[yg][xg] && map[ys][xs]!=0){
			temp=map[ys][xs];
			map[ys][xs]=0;
			func(ys,xs);
		}/*
		for(i=1;i<=10;i++){
			for(j=1;j<=10;j++){
				printf("%d ",map[i][j]);
			}
			printf("\n");
		}*/
		if(flg==1){
			printf("OK\n");
		}
		else {
			printf("NG\n");
		}
	}
	return 0;
}
void func(int y,int x){
	int dy[4]={0,1,0,-1},dx[4]={1,0,-1,0};
	int i,xx,yy;
	if(flg==0){
		for(i=0;i<4;i++){
			yy=y+dy[i];
			xx=x+dx[i];
			if(yy<=h && yy>=1 && xx<=w && xx>=1 && map[yy][xx]==temp){
				map[yy][xx]=0;
				if(xg==xx && yg==yy){
					flg=1;
					break;
				}
				func(yy,xx);
			}
		}
	}
}

C++: #include <iostream>
#include <queue>
#include <cstring>
const int MAX_W = 100, MAX_H = 100;

typedef std::pair<int,int> P;
int map[MAX_H + 1][MAX_W + 1], w, h;

int bfs(P sp, P gp, int c){
	//½±Æª é©ði[
	int f[MAX_H + 1][MAX_W + 1] = {{0}};
	std::queue<P> q;
	q.push(P(sp.first, sp.second));
	
	while(q.size()){
		P p = q.front(); q.pop();
		//S[Å«½ç¬÷
		if(p.first == gp.first && p.second == gp.second)return 1;
		
		int vy[4] = {-1, 1, 0, 0}, vx[4] = {0, 0, -1, 1};
		for(int i=0;i<4;i++){
			int nx = p.first + vx[i], ny = p.second + vy[i];
			if(nx >= 0 && nx <= w && ny >= 0 && ny <= h && map[ny][nx] == c && !f[ny][nx])
				q.push(P(nx,ny)), f[ny][nx] = 1;
		}
	}

	//ÅãÜÅS[Å«È¢Èç¸s
	return 0;
}

int main(){
	P sp, gp;
	while(std::cin >> w >> h, w && h){
		memset(map,0,sizeof(map));
		std::cin >> sp.first >> sp.second;
		std::cin >> gp.first >> gp.second;

		int n;
		std::cin >> n;
		//ubNÌÝu
		while(n--){
			int c, d, x, y;
			std::cin >> c >> d >> x >> y;
			
			int mx, my;
			if(d)//w < h
				my = 4, mx = 2;
			else//w > h
				mx = 4, my = 2;
			for(int i=y;i<y+my;i++)
				for(int j=x;j<x+mx;j++)
					map[i][j] = c;
		}

		int sc = map[sp.second][sp.first];

		//bfsÅS[Å«é©mF
		if(bfs(sp, gp, sc))std::cout << "OK" << std::endl;
		else std::cout << "NG" << std::endl;
	}
}