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 <stdio.h>
#include <queue>
#include <iostream>



#define MAX 150

int map[MAX][MAX];

void makemap(int c, int d, int x, int y);

int bfs(int xs,int ys,int xg,int yg);

int main()
{
	int w,h,xs,ys,xg,yg,n,c,d,x,y;
	//int flag=1;
	while(1)
	{
		scanf("%d%d",&w,&h);
		if(w==0 && h==0)
			return 0;
		scanf("%d%d",&xs,&ys);
		scanf("%d%d",&xg,&yg);
		scanf("%d",&n);

		/*w=20;
		h=20;
		if (flag==0)
		{
			xs=1;
			ys=1;
			xg=9;
			yg=9;
			n=7;
		}
		else
		{
			xs=9;
			ys=9;
			xg=1;
			yg=1;
			n=6;
		}サンプルデータ入力*/
		for(int i=0;i<MAX;i++)
			for(int j=0;j<MAX;j++)
				map[i][j]=0;
		/*if (flag==0)
		{
			makemap(2,0,1,1);
			makemap(5,1,1,3);
			makemap(2,1,3,3);
			makemap(1,1,5,2);
			makemap(5,1,7,3);
			makemap(2,0,2,7);
			makemap(2,0,6,8);
		}
		else
		{
			makemap(2,0,1,1);
			makemap(1,0,5,1);
			makemap(2,1,1,3);
			makemap(5,0,1,7);
			makemap(3,1,5,5);
			makemap(4,1,8,5);
		}サンプルデータ入力２*/

		for(int i=0;i<n;i++)
		{
			scanf("%d%d%d%d",&c,&d,&x,&y);
			makemap(c,d,x,y);
		}
		

		/*for(int i=0;i<MAX;i++)
		{
			for(int j=0;j<MAX;j++)
				printf("%d",map[i][j]);
			printf("\n");
		}マップの表示*/

		if(bfs(xs,ys,xg,yg)==0)
			printf("OK\n");
		else
			printf("NG\n");
}
	return 0;
}

void makemap(int c, int d, int x, int y)
{
	if(d==0)
		for(int i=x+1;i<x+5;i++)
			for(int j=y+1;j<y+3;j++)
				map[i][j]=c;
	else
		for(int i=x+1;i<x+3;i++)
			for(int j=y+1;j<y+5;j++)
				map[i][j]=c;
}

int bfs(int xs,int ys,int xg,int yg)
{
	int startcolor=map[xs][ys];
	int nowx=xs,nowy=ys;
	using namespace std;
	queue<int> x;
	queue<int> y;
	while(1)
	{
		if(nowx==xg && nowy == yg && map[nowx][nowy]==startcolor )
			return 0;
		map[nowx][nowy]=0;
		if(map[nowx-1][nowy]==startcolor)
		{
			x.push(nowx-1);
			y.push(nowy);
		}
		if(map[nowx][nowy-1]==startcolor)
		{
			x.push(nowx);
			y.push(nowy-1);
		}
		if(map[nowx][nowy+1]==startcolor)
		{
			x.push(nowx);
			y.push(nowy+1);
		}
		if(map[nowx+1][nowy]==startcolor)
		{
			x.push(nowx+1);
			y.push(nowy);
		}
		if(x.empty()==1 && y.empty()==1)
			return 1;
		nowx=x.front();
		nowy=y.front();
		x.pop();
		y.pop();
	}
	/*bool visit[MAX][MAX];
	for(int i=0;i<MAX;i++)
		for(int j=0;j<MAX;j++)
			visit[i][j]=0;
	while(1)
	{
		//visit[nowx][nowy]=1;
		if(nowx==xg && nowy == yg && map[nowx][nowy]==startcolor )
			return 0;
		map[nowx][nowy]=0;
		if(map[nowx-1][nowy]==startcolor && visit[nowx-1][nowy]==0)
		{
			x.push(nowx-1);
			y.push(nowy);
		}
		if(map[nowx][nowy-1]==startcolor && visit[nowx][nowy-1]==0)
		{
			x.push(nowx);
			y.push(nowy-1);
		}
		if(map[nowx][nowy+1]==startcolor && visit[nowx][nowy+1]==0)
		{
			x.push(nowx);
			y.push(nowy+1);
		}
		if(map[nowx+1][nowy]==startcolor && visit[nowx+1][nowy]==0)
		{
			x.push(nowx+1);
			y.push(nowy);
		}
		if(x.empty()==1 && y.empty()==1)
			return 1;
		nowx=x.front();
		nowy=y.front();
		x.pop();
		y.pop();
	}*/
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>

using namespace std ;

int w ,h ,n ;
int sx ,sy ,gx ,gy ;

struct P
{
	int x ;
	int y ;
} ;

bool came[ 110 ][ 110 ] ;

int map[ 110 ][ 110 ] ;

void high( int x ,int y ,int c )
{
	for( int i = 0 ; i < 4 ; i++ )
	{
		for( int j = 0 ; j < 2 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

void wide( int x ,int y ,int c )
{
	for( int i = 0 ; i < 2 ; i++ )
	{
		for( int j = 0 ; j < 4 ; j++ )
			map[ y + i ][ x + j ] = c ;
	}

	return ;
}

int main()
{
	while( cin >> w >> h )
	{
		if( w == h && !w )
			return 0 ;
		cin >> sx >> sy >> gx >> gy >> n ;
	memset( came ,false ,sizeof came ) ;
	memset( map ,0 ,sizeof map ) ;

	stack< P > st ;

	int c ,d ,x ,y ;
	int d1 ,d2 ;
	for( int k = 0 ; k < n ; k++ )
	{
		cin >> c >> d >> x >> y ;
		d ? high( x ,y ,c ) : wide( x ,y ,c ) ;
		/*if( d )
		{
			d1 = 2 ;
			d2 = 4 ;
		}
		else
		{
			d1 = 4 ;
			d2 = 2 ;
		}
		for( int i = 0 ; i < d1 ; i++ )
		{
			for( int j = 0 ; j < d2 ; j++ )
				map[ y + i ][ x + j ] = c ;
		}*/
	}
/*
for( int i = 0 ; i <= h + 1 ; i++ )
{
	for( int j = 0 ; j <= w + 1 ; j++ )
		cout << map[ i ][ j ] ;
	cout << endl ;
}
*/
	if( map[ sy ][ sx ] != map[ gy ][ gx ] )
	{
		printf( "NG\n" ) ;
		continue ;
	}

	c = map[ gy ][ gx ] ;

	for( int i = 1 ; i <= h ; i++ )
	{
		for( int j = 1 ; j <= w ; j++ )
		{
			if( c == map[ i ][ j ] )
				came[ i ][ j ] = true ;
		}
	}

	d = 1 ;
	P l ;
	l.x = sx ;
	l.y = sy ;
	st.push( l ) ;

	came[ sy ][ sx ] = false ;

	while( !st.empty() )
	{

		P p = st.top() ;
		st.pop() ;

		if( p.x == gx && p.y == gy )
		{
			d = 0 ;
			break ;
		}
		for( int i = 0 ; i < 4 ; i++ )
		{
			int mx[] = { 1 ,0 ,0 ,-1 } ;
			int my[] = { 0 ,1 ,-1 ,0 } ;
			int xx = p.x + mx[ i ] ;
			int yy = p.y + my[ i ] ;
			if( xx > 0 && x <= w && yy > 0 && yy <= h && came[ yy ][ xx ] )
			{
				came[ yy ][ xx ] = false ;
				l.x = xx ;
				l.y = yy ;
				st.push( l ) ;
			}
		}
	}
	d ? printf( "NG\n" ) : printf( "OK\n" ) ;

	}
}