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 c){
  if(F[Y][X] != c){
    return;
  }
  
  F[Y][X] = -2;
  DFS(Y-1,X  ,c);
  DFS(Y  ,X+1,c);
  DFS(Y+1,X  ,c);
  DFS(Y  ,X-1,c);
}
  
  
int main(){
  int w,h,xs,ys,xg,yg,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;

    for(int i=0; i<20; i++){
      for(int j=0; j<20; j++){
        F[i][j]=-1;
      }
    }
      
    cin >> xs >> ys >> xg >> yg >> n;
  
  
    for(int i=0;i<n;i++){
      int c,d,x,y;
      cin >> c >> d >> x >> y;
      if(d == 0){
        for(int j=0;j<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }

  if(F[xs][ys] == 0){
    cout << "NG" << endl;
  } else {
    DFS(xs,ys,F[xs][ys]);
  
    if(F[xg][yg] == -1){
      cout << "OK" << endl;
    } else {
      cout << "NG" <<endl;
    }
  }

}
}

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



typedef vector<vector<int> > Matrix;
int w,h,xs,ys,xg,yg,n,color;
string res = "NG";
void write(Matrix &board,int c, int d, int x, int y){
  int width,length;
  if(d == 0){ width = 4; length =2; }
  if(d == 1){ width = 2; length =4; }
  for(int i=0; i<width; ++i){
    for(int j=0; j<length; ++j)
      board[x+i][y+j]=c;
  }
}
void func(Matrix &board,int nx,int ny){
  if(board[nx][ny] == 0){
    res = "NG";
    return;
  }
  if( nx==xg && ny==yg){
    res = "OK";
    return;
  }
  board[nx][ny] = 0;
  if( 0<=nx-1 && color==board[nx-1][ny])
    func(board,nx-1,ny);
  if( 0<=ny-1 && color==board[nx][ny-1])
    func(board,nx,ny-1);
  if( nx+1<=w && color==board[nx+1][ny])
    func(board,nx+1,ny);
  if( ny+1<=h && color==board[nx][ny+1])
    func(board,nx,ny+1);
}


int main(void){
  int c,d,x,y;
  while(cin >> w >> h,w||h){
    if( w==0 && h==0) return 0;
    res = "NG";
    cin >> xs >> ys >> xg >> yg >> n;
    xs--; ys--; xg--; yg--;
    Matrix board(w, vector<int>(h,0));
    for(int i=0; i<n; ++i){
      cin >> c >> d >> x >> y;
      --x; --y;
      write(board,c,d,x,y);
    }
    color = board[xs][ys];
    func(board,xs,ys);
    cout << res << endl;
    board.clear();
  }
  return 0;
}

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

int F[101][102];

void DFS(int Y, int X, int c) {
	//cout << Y << " " << X << endl;
	if (F[Y][X] != c)
		return;
	F[Y][X] = 10;
	DFS(Y - 1, X, c);//???
					 //DFS(Y - 1, X+1, A_ito);//??????
	DFS(Y, X + 1, c);//???
					 //DFS(Y + 1, X+1, A_ito);//??????
	DFS(Y + 1, X, c);//???
					 //DFS(Y + 1, X-1, A_ito);//??????
	DFS(Y, X - 1, c);//???
					 //DFS(Y - 1, X-1, A_ito);//??????
}


int main()
{
	int xs, ys, xg, yg, n;
	int c, d, x, y;
	int W = 1, H = 1;

	while ((W != 0) && (H != 0)) {
		cin >> W >> H;
		cin >> xs >> ys >> xg >> yg >> n;
		for (int i = 1;i <= n;i++) {
			cin >> c >> d >> x >> y;
			if (d == 0) {
				F[x][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y] = c;
				F[x + 1][y + 1] = c;
				F[x + 2][y] = c;
				F[x + 2][y + 1] = c;
				F[x + 3][y] = c;
				F[x + 3][y + 1] = c;
			}
			if (d == 1) {
				F[x][y] = c;
				F[x + 1][y] = c;
				F[x][y + 1] = c;
				F[x + 1][y + 1] = c;
				F[x][y + 2] = c;
				F[x + 1][y + 2] = c;
				F[x][y + 3] = c;
				F[x + 1][y + 3] = c;
			}
		}
		if (F[ys][xs] != 0)
			DFS(ys, xs, F[ys][xs]);

		if (F[yg][xg] == 10) {
			cout << "OK" << endl;
		}
		else { cout << "NG" << endl; }
		for (int i = 0;i < H;i++) {
			for (int j = 0;j < W;j++) {
				F[i][j] = 0;
			}
		}
	}

	return 0;
}

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

int map[102][102];

void route(int w, int h, int color) {
	if (map[w][h] != color)
		return;
	map[w][h] = 10;
	route(w, h + 1, color);
	route(w + 1, h, color);
	route(w, h - 1, color);
	route(w - 1, h, color);
}


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

	while (1) {
		for (int i = 0; i < 102; i++)
			for (int j = 0; j < 102; j++)
				map[i][j] = 0;
		cin >> w >> h;		
		if (w == 0 && h == 0)
			break;

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

		for (int i = 0; i<n; i++) {
			cin >> c >> d >> x >> y;
			if (d == 1) {
				for (int j = 0; j < 4; j++)
					map[j + x][y] = map[j + x][y + 1] = c;
			}
			else {
				for (int j = 0; j < 4; j++)
					map[x][y + j] = map[x + 1][y + j] = c;
			}
		}

		color = map[xs][ys];
		route(xs, ys, color);
		
		if (map[xg][yg]==10)
			cout << "OK" << endl;
		else
			cout << "NG"<<endl;
	}

	return 0;
}

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

int C[102][102];
int ans;
int xg,yg;

void meiro(int W,int H,int c){
  if(W==xg && H==yg){
    ans = 1;
    return;
  }

  if(C[W][H]!=c){
    return;
  }

  C[W][H] = '.';

  meiro(W-1,H  ,c);
  meiro(W  ,H+1,c);
  meiro(W+1,H  ,c);
  meiro(W  ,H-1,c);
}

int main(){
  while(1){
    int w,h;
    cin >> w >> h;

    for(int i=0;i<w;i++){
      for(int j=0;j<h;j++){
        C[i][j] = 0;
      }
    }

    if(w==0 && h==0){
      break;
    }

    int xs,ys;
    cin >> xs >> ys;

    cin >> xg >> yg;

    int n;
    cin >> n;
    int c,d,x,y;

    int cbase;

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

      if(x == xs &&y == ys){
        cbase = c;
      }

      if(d == 0 && c == cbase){
        for(int j=x;j<x+4;j++){
          for(int k=y;k<y+2;k++){
            C[j][k]=c;
          }
        }
      }
      if(d==1 && c==cbase){
        for(int j = x;j<x+2;j++){
          for(int k=y;k<y+4;k++){
            C[j][k]=c;
          }
        }
      }
    }
    ans = 0;
    meiro(xs,ys,cbase);

    if(ans == 1){
      cout << "OK" << endl;
    }
    if(ans != 1 || C[xs][ys] == 0){
      cout << "NG" << endl;
    }
  }

  return 0;
}