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>
#include<vector>
#include<list>

typedef struct block
{
	int x;
	int y;
	int h;
	int w;
	int color;
}block;

block blocks[1280];

std::queue<int> que;
std::list<int> adjacive[1280];

void makelist(int n);
bool BFS(int start,int goal);

int main()
{
	int n,w,h,xs,ys,xg,yg,start,goal;
	while(1)
	{
		while(!que.empty()){que.pop();}
		start=-1;
		goal=-1;
		std::cin>>w>>h;
		if(w==0&&h==0)break;
		std::cin>>xs>>ys>>xg>>yg>>n;
		
		
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			std::cin>>c>>d>>x>>y;
			blocks[i].color=c;
			blocks[i].x=x;
			blocks[i].y=y;
			if(d==0)
			{
				blocks[i].h=2;
				blocks[i].w=4;
			}
			else
			{
				blocks[i].h=4;
				blocks[i].w=2;
			}
			if(blocks[i].x<=xs&&blocks[i].x+blocks[i].w-1>=xs&&blocks[i].y<=ys&&blocks[i].y+blocks[i].h-1>=ys)
			{
				start=i;
			}
			else if(blocks[i].x<=xg&&blocks[i].x+blocks[i].w-1>=xg&&blocks[i].y<=yg&&blocks[i].y+blocks[i].h-1>=yg)
			{
				goal=i;
			}
		}

		makelist(n);

		if(BFS(start,goal))
		{
			std::cout<<"OK"<<std::endl;
		}
		else
		{
			std::cout<<"NG"<<std::endl;
		}
	}
	return 0;
}

void makelist(int n)
{
#define x1 blocks[i].x
#define y1 blocks[i].y
#define h1 blocks[i].h
#define w1 blocks[i].w
#define x2 blocks[j].x
#define y2 blocks[j].y
#define h2 blocks[j].h
#define w2 blocks[j].w

	for(int i=0;i<n;i++)
	{
		adjacive[i].clear();
		for(int j=0;j<n;j++)
		{
			if(blocks[i].color==blocks[j].color)
			{
				if((x1==x2+w2&&y1<=y2+h2-1&&y1+h1-1>=y2)||(x2==x1+w1&&y1<=y2+h2-1&&y1+h1-1>=y2)||(y1==y2+h2&&x1<=x2+w2-1&&x1+w1-1>=x2)||(y2==y1+h1&&x1<=x2+w2-1&&x1+w1-1>=x2))
				{
					adjacive[i].push_back(j);
				}
			}
		}
	}
}

bool BFS(int start,int goal)
{
	int survey;

	if(start==-1||goal==-1)return false;

	que.push(start);
	
	while(!que.empty())
	{
		survey=que.front();
		que.pop();
		for(std::list<int>::iterator it=adjacive[survey].begin();it!=adjacive[survey].end();it++)
		{
				que.push(*it);
		}
		adjacive[survey].clear();
		if(survey==goal)
		{
			return true;
		}
	}
	return false;
}

C++: #include<stdio.h>
#include<string.h>
void haichi(void);
void Block(int,int);
int c,d,x,y,xg,yg,M,Flag;
int MAP[101][101],MF[101][101];
int main(void)
{
    int w,h,xs,ys,n;
    while(1){
        Flag=0;
        memset(MAP,0,sizeof(MAP));
        memset(MF,0,sizeof(MF));
        scanf("%d %d",&w,&h);
        if(w == 0 && h == 0) break;
        scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
        scanf("%d",&n);
        for(int i=0;i<n;i++){
            scanf("%d %d %d %d",&c,&d,&x,&y);
            haichi();
        }
        /*for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                printf("%d",MAP[i][j]);
            }
            printf("\n");
        }*/
        M = MAP[ys][xs];//
        if(MAP[ys][xs] == MAP[yg][xg])
            Block(xs,ys);
        if(Flag==1)
            printf("OK\n");
        else
            printf("NG\n");
    }
    return 0;
}
 
void haichi(void)
{
    if(d==0){
        MAP[y][x]=c;MAP[y][x+1]=c;MAP[y][x+2]=c;MAP[y][x+3]=c;
        MAP[y+1][x]=c;MAP[y+1][x+1]=c;MAP[y+1][x+2]=c;MAP[y+1][x+3]=c;
    }
    else if(d==1){
        MAP[y][x]=c;MAP[y][x+1]=c;
        MAP[y+1][x]=c;MAP[y+1][x+1]=c;
        MAP[y+2][x]=c;MAP[y+2][x+1]=c;
        MAP[y+3][x]=c;MAP[y+3][x+1]=c;
    }
}
 
void Block(int X,int Y)
{
    MF[Y][X] = 1;
    //printf("%d",M);
    if(X == xg && Y == yg)
        Flag = 1;
    if(MAP[Y-1][X] == M && MF[Y-1][X] == 0) Block(X,Y-1); //???
    if(MAP[Y+1][X] == M && MF[Y+1][X] == 0) Block(X,Y+1); //???
    if(MAP[Y][X-1] == M && MF[Y][X-1] == 0) Block(X-1,Y); //???
    if(MAP[Y][X+1] == M && MF[Y][X+1] == 0) Block(X+1,Y); //???
}

C++: #include <iostream>
using namespace std;
int w,h, n;
int xs,ys, xg,yg;
int c,d,x,y;
char board[100][100];

bool rec(int y, int x, char c){
  if( y<0 || x<0 )
    return false;
  if( y>=h || x>=w )
    return false;

  if( board[y][x] !=c )
    return false;

  if( y==yg && x==xg )
    return true;
  board[y][x] = 9;

  int dx[]={0,0,1,-1}, dy[]={1,-1,0,0};
  for( int z=0;z<4;z++ ){
    if( rec(y+dy[z], x+dx[z], c) )
      return true;
  }

  return false;
}
int main(){
  while(cin>>w>>h,w){
    for( int i=0;i<h;i++ )
      for( int j=0;j<w;j++ )
	board[i][j] = 0;

    cin >> xs >> ys;
    cin >> xg >> yg;
    xs--;ys--;
    xg--;yg--;

    cin >> n;
    while(n--){
      cin >> c >> d >> x >> y;
      x--; y--;
      int li=d?4:2; // d==0 => yoko
      int lj=d?2:4;

      for( int i=0;i<li;i++ )
	for( int j=0;j<lj;j++ )
	  board[y+i][x+j] = c;
    }
    if( rec(ys, xs, board[ys][xs]) )
      cout << "OK" << endl;
    else
      cout << "NG" << endl;
    /*
    for( int i=0;i<h;i++ ){
      for( int j=0;j<w;j++ )
	cout << (int)board[i][j];
      cout << endl;
    }
    */
  }

  return 0;
}