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;
#define MAX 100

int map[MAX][MAX];
int xs, ys, xg, yg;
int n;
int w, h;
int c, d, x, y;
int count = 0;
int color;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

void jadge(int x, int y){
	if(count == 0){
		if(0 <= x && x < w && 0 <= y && y < h && map[x][y] == color && map[x][y] != 9){
			map[x][y] = 9;
			if(x == xg && y == yg){
				count = 1;
				return;
			}
			for(int i=0; i < 4; i++){
				jadge(x+dx[i], y+dy[i]);
			}
		}
	}
}
int main(){
	while(1){
		count = 0;

		for(int i=0; i < MAX; i++){
			for(int j=0; j< MAX; j++){
				map[i][j] = 0;
			}
		}

		cin >> w >> h;
		if(w == 0 && h == 0) break;

		cin >> xs >> ys;
		cin >> xg >> yg;
		xs--; ys--; xg--; yg--;
		cin >> n;
		for(int i=0; i < n; i++){
			cin >> c >> d >> y >> x;

			for(int i=0;  i < 4; i++){
				for(int j=0; j < 2; j++){
					if(d == 1){
						map[x-1+i][y-1+j] = c;
					}
					else{
						map[x-1+j][y-1+i] = c;
					}
				}
			}
		}
		if(map[xs][ys] != map[xg][yg]){
			cout << "NG" << endl;
			continue;
		}
		else if(map[xs][ys] == 0 || map[xg][yg] == 0){
			cout << "NG" << endl;
			continue;
		}
		color = map[xs][ys];

		jadge(xs, ys);

		if(count == 1) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

C++: #include<stdio.h>
#include<string.h>
void haichi(void);
int Block(int,int);
int c,d,x,y,xg,yg,w,h,M,Flag;
int MAP[102][102],MF[102][102];
int main(void)
{
	int 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(Block(xs,ys))
			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;
	}
}

int Block(int X,int Y)
{
	
	//printf("%d",M);
	printf("%d %d\n",X,Y);
	if(X == xg && Y == yg)
		return 1;
	if(MAP[Y][X] != M || MF[Y][X] == 1 || X < 1 || Y < 1 || X > w || Y > h) return 0;
	MF[Y][X] = 1;
	return Block(X,Y-1) || Block(X,Y+1) || Block(X-1,Y) || Block(X+1,Y);
}

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

int F[102][102];

void
DFS (int Y, int X, int A)
{
  if (F[Y][X] != A)
    return;

  F[Y][X] = 7;

  DFS (Y - 1, X, A);
  DFS (Y, X + 1, A);
  DFS (Y + 1, X, A);
  DFS (Y, X - 1, A);
}

int
main ()
{
  int w, h;
  int xs, ys;
  int xg, yg;
  int n;
  int c, d, x, y;

  while (true)
    {
      cin >> w >> h;
      if (w == 0 && h == 0)
	break;
      cin >> xs >> ys;
      cin >> xg >> yg;
      cin >> n;

      for (int i = 0; i < n; i++)
	{
	  cin >> c >> d >> x >> y;
	  if (d == 0)
	    {
	      for (int a = 0; a < 4; a++)
		{
		  for (int b = 0; b < 2; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}

	    }
	  else
	    {
	      for (int a = 0; a < 2; a++)
		{
		  for (int b = 0; b < 4; b++)
		    {
		      F[y + b][x + a] = c;
		    }
		}
	    }

	}


      if (F[ys][xs] == 0 || F[ys][xs] == 1 || F[ys][xs] == 2 || F[ys][xs] == 3
	  || F[ys][xs] == 4 || F[ys][xs] == 5)
	{
	  DFS (ys, xs, F[ys][xs]);
	}

      if (F[yg][xg] == F[ys][xs])
	{
	  cout << "OK" << endl;
	}
      else
	{
	  cout << "NG" << endl;
	}
   
    /*for (int y = 0; y < h; y++)
	{
	  for (int x = 0; x < w; x++)
	    {
	      cout << F[y][x];
	    }
         cout << endl;
	}*/
   
    for (int y = 1; y <= h; y++)
	{
	  for (int x = 1; x <= w; x++)
	    {
	      F[y][x] = 0;
	    }
	}

    
   
    }

  return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;

int w, h;
vector < vector <int> > block_map;
vector < vector <bool> > visited;

int xs, ys;
int xg, yg;

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

bool dfs( int x, int y )
{
	if ( block_map[y][x] != block_map[yg][xg] )
		return false;
	if ( x == xg && y == yg )
		return true;

	for ( int i = 0; i < 4; i++ )
	{
		int nx = x + dx[i];
		int ny = y + dy[i];
		if ( nx < 0 || nx >= w || ny < 0 || ny >= h )
			continue;

		if ( visited[ny][nx] == false && block_map[ny][nx] == block_map[ys][xs] )
		{
			visited[ny][nx] = true;
			if ( dfs( nx, ny ) )
			{
				return true;
			}
			visited[ny][nx] = false;
		}
	}

	return false;
}

int main( void )
{
	while ( 1 )
	{
		cin >> w >> h;
		if ( w == 0 && h == 0 )
			break;

		block_map = vector < vector <int> >( h, vector <int>(w,0) );
		visited = vector < vector <bool> >( h, vector <bool>(w,false) );

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

		xs--;
		ys--;
		xg--;
		yg--;

		int n;
		cin >> n;
		for ( int i = 0; i < n; i++ )
		{
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			x--;
			y--;

			if ( d == 0 )
			{
				for ( int by = 0; by < 2; by++ )
				{
					for ( int bx = 0; bx < 4; bx++ )
					{
						block_map[y+by][x+bx] = c;
					}
				}
			}
			else
			{
				for ( int by = 0; by < 4; by++ )
				{
					for ( int bx = 0; bx < 2; bx++ )
					{
						block_map[y+by][x+bx] = c;
					}
				}
			}
		}

		visited[ys][xs] = true;
		if ( dfs( xs, ys ) )
			cout << "OK" << endl;
		else
			cout << "NG" << endl;

	}
	return 0;
}