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;
struct cordinate{
        int y;
        int x;
};
cordinate SIZE,Start,Goal;
struct Blocks{
        int color;
        int direction;
        int y;
        int x;
};
Blocks block[100];
int N,board[100][100];
int Color,dp[100][100];
int recursion(int y,int x){
        int res=0;
        if(y==Goal.y && x==Goal.x){
                res=1;
        }
        else{
                dp[y][x]=0;
                if(board[y+1][x]==Color && dp[y+1][x]==-1)
                        res+=recursion(y+1,x);
                if(board[y-1][x]==Color && dp[y-1][x]==-1)
                        res+=recursion(y-1,x);
                if(board[y][x+1]==Color && dp[y][x+1]==-1)
                        res+=recursion(y,x+1);
                if(board[y][x-1]==Color && dp[y][x-1]==-1)
                        res+=recursion(y,x-1);
        }
        return dp[y][x]=res;
}
int main(){
        while(true){
                for(int i=0 ; i<100 ; i++ )
                        for(int j=0 ; j<100 ; j++ )
                                dp[i][j]=-1;
                cin >> SIZE.x >> SIZE.y;
                if(SIZE.x+SIZE.y==0)
                        break;
                cin >> Start.x >> Start.y;
                cin >> Goal.x >> Goal.y;
                cin >> N;
                for(int i=0 ; i<N ; i++ ){
                        cin >> block[i].color >> block[i].direction;
                        cin >> block[i].x >> block[i].y;
                        if(block[i].direction){
                                for(int l=block[i].y ; l<block[i].y+4 ; l++ ){
                                        for(int j=block[i].x ; j<block[i].x+2 ; j++ ){
                                                board[l][j]=block[i].color;
                                        }
                                }
                        }
                        else{
                                for(int l=block[i].y ; l<block[i].y+2 ; l++ ){
                                        for(int j=block[i].x ; j<block[i].x+4 ; j++ ){
                                                board[l][j]=block[i].color;
                                        }
                                }
                        }
                }
                Color=board[Start.y][Start.x];
                if(recursion(Start.y,Start.x)>0)
                        cout <<"OK"<<endl;
                else
                        cout <<"NG"<<endl;
        }
        return 0;
}

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

#define size_max 100+10

#define Y first
#define X second

int mx[4] = { 1,-1,0,0 };
int my[4] = { 0,0,1,-1 };

int map[size_max][size_max];


void paint(int c, int y, int x, int H, int W)
{
	int i, j;
	for (i = y; i < y + H; i++)
	{
		for (j = x; j < x + W; j++)
		{
			map[i][j] = c;
		}
	}
}


void chek(int w, int h)
{
	int i, j;
	for (i = 0; i <= h + 1; i++)
	{
		for (j = 0; j <= w + 1; j++)
		{
			cout << map[i][j];
		}
		cout << endl;
	}
}


typedef pair<int, int> PR;

int main(void)
{
	PR now, tmp;
	queue<PR> QU;

	int w, h;
	int xs, ys, xg, yg, n;
	int c, d, set_x, set_y;

	int i, j;

	while ((cin >> w >> h), w != 0 && h != 0)
	{
		memset(map, 0, sizeof map);

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

		for (i = 0; i < n; i++)
		{
			cin >> c >> d >> set_x >> set_y;

			if (d == 0)
			{
				paint(c, set_y, set_x, 2, 4);
			}
			else
			{
				paint(c, set_y, set_x, 4, 2);
			}
		}

		chek(w, h);

		if (map[ys][xs] == 0)
		{
			cout << "NG\n";
			continue;
		}

		now = make_pair(ys, xs);
		QU.push(now);

		bool goal = false;
		while (!QU.empty())
		{
			now = QU.front();
			QU.pop();

			if (map[now.Y][now.X] != -1)
			{
				map[now.Y][now.X] = -1;

				if (now.Y == yg && now.X == xg)
				{
					goal = true;
					while (!QU.empty())
					{
						QU.pop();
					}
					break;
				}

				for (i = 0; i < 4; i++)
				{
					if (map[now.Y + my[i]][now.X + mx[i]] == c)
					{
						tmp = make_pair(now.Y + my[i], now.X + mx[i]);
						QU.push(tmp);
					}
				}
			}
		}

		if (goal)
		{
			cout << "OK\n";
		}
		else
		{
			cout << "NG\n";
		}

	}

	return 0;
}