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;

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] == 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<cstring>
using namespace std;
int map[110][110];
int com[110][110];
int lx,ly,sx,sy,gx,gy;
int py[4]={1,0,-1,0};
int px[4]={0,1,0,-1};
int fl;
int mei(int zx,int zy ,int cei[][110])
{
	int i;
	if(fl) return 0;
	if(zx==gx && zy==gy)
	{
		fl=1;
		return 0;
	}
	cei[zy][zx]=1;
	for(i=0;i<4;i++)
	{
		if(cei[zy+py[i]][zx+px[i]]==0 && map[sy][sx]==map[zy+py[i]][zx+px[i]])
		{
			mei(zx+px[i],zy+py[i],cei);
			
		}
	}
	cei[zy][zx]=0;
	return 0;
}
int main()
{
	int n,col,muk,vx,vy;
	int i,j,t;
	while(cin >> lx >> ly, lx)
	{
		fl=0;
		cin >> sx >> sy >> gx >> gy >> n;
		memset(map,0,sizeof(map));
		memset(com,0,sizeof(com));
		for(i=0;i<n;i++)
		{
			cin >> col >> muk >> vx >> vy;
			if(muk==0)
			{
				for(j=vy;j<2+vy;j++)
				{
					for(t=vx;t<4+vx;t++)
					{
						map[j][t]=col;
					}
				}
			}
			else
			{
				for(j=vy;j<4+vy;j++)
				{
					for(t=vx;t<2+vx;t++)
					{
						map[j][t]=col;
					}
				}
			}
		}
		if(map[sy][sx]!=map[gy][gx])
		{
			cout << "NG" << endl;
			continue;
		}
		mei(sx,sy,com);
		if(fl) cout << "OK" << endl;
		else cout << "NG" << endl;
	}
	return 0;
}

C++: #include <iostream>

using namespace std;

int w, h;
int xg, yg;
int data[101][101];
int dx[]={0, 1, 0, -1};
int dy[]={-1, 0, 1, 0};
bool visited[101][101];
bool dfs(int, int, int);

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

    int xs, ys, n;
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
    for(int i=0;i<=h;i++){
      for(int j=0;j<=w;j++){
	data[i][j]=0;
      }
    }
    for(int i=0;i<n;i++){
      int c, d, x, y;
      cin >> c >> d >> x >> y;
      if(d==0){
	for(int i=0;i<2;i++){
	  for(int j=0;j<4;j++){
	    data[i+y][j+x]=c;
	  }
	}
      }else{
	for(int i=0;i<4;i++){
	  for(int j=0;j<4;j++){
	    data[i+y][j+x]=c;
	  }
	}
      }
    }
    for(int i=0;i<=h;i++){
      for(int j=0;j<=w;j++){
	visited[i][j]=false;
      }
    }

    if(dfs(ys, xs, data[ys][xs])){
      cout << "OK" << endl;
    }else{
      cout << "NG" << endl;
    }
  }
  return 0;
}

bool dfs(int y, int x, int c){
  if(y==yg && x==xg){
    return true;
  }
  visited[y][x]=true;
  bool ans=false;
  for(int i=0;i<4;i++){
    int ty=y+dy[i];
    int tx=x+dx[i];
    if(ty>0 && ty<=h){
      if(tx>0 && tx<=w){
	if(data[ty][tx]==c && !visited[ty][tx]){
	  ans=dfs(ty, tx, c);
	  if(ans) break;
	}
      }
    }
  }
  return ans;
}

C++: #include <iostream>
#include <vector>

using namespace std;
typedef pair<int, int> P;
int dx[] = {-1, 0, 0, 1};
int dy[] = {0, -1, 1, 0};
bool ok = false;
int w, h;
vector< vector<int> > Field;
P goal;

void DFS(int x, int y, int c)
{
	if(x == goal.first && y == goal.second)
	{
		ok = true;
		return;
	}
	else
	{
		Field[y][x] = -1;
	}
	for(int i = 0; i < 4; ++i)
	{
		int nx = x + dx[i];
		int ny = y + dy[i];
		if(0 <= nx && nx < w && 0 <= ny && ny < h && Field[ny][nx] == c)
		{
			DFS(nx, ny, c);
		}
	}
}

void solve()
{
	while(cin >> w >> h, w || h)
	{
		ok = false;
		Field.resize(h);
		for(int i = 0; i < h; ++i)
		{
			Field[i].resize(w);
			for(int j = 0; j < w; ++j)
			{
				Field[i][j] = 0;
			}
		}
		P start;
		cin >> start.first >> start.second;
		--start.first; --start.second;
		cin >> goal.first >> goal.second;
		--goal.first; --goal.second;
		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 i = 0; i < 2; ++i)
				{
					for(int j = 0; j < 4; ++j)
					{
						Field[y + i][x + j] = c;
					}
				}
			}
			else if(d == 1) 
			{
				for(int i = 0; i < 4; ++i)
				{
					for(int j = 0; j < 2; ++j)
					{
						Field[y + i][x + j] = c;
					}
				}
			}
		}
		DFS(start.first, start.second, Field[start.second][start.first]);
		if(ok)
		{
			cout << "OK" << endl;
		}
		else
		{
			cout << "NG" << endl;
		}
	}
}

int main()
{
	solve();
	return(0);
}