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++: // based on http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2784229#1
#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
int needleX[4] = { -1,0,1,0 };
int needleY[4] = { 0,1,0,-1 };
bool dfs(int x, int y, int goalx, int goaly, std::vector<std::vector<bool>>&canGo) {
  if (x == goalx && y == goaly) { return true; }
  canGo[y][x] = false;
  for (int i = 0; i < 4; i++) {
    int next_x = x + needleX[i];
    int next_y = y + needleY[i];
 
    if (canGo[next_y][next_x]) {
      bool flag = dfs(next_x, next_y, goalx, goaly, canGo);
      if (flag)
        return true;
    }
  }
  return false;
}
int main(void) {
  int h, w, n;
  std::cin >> w >> h;
  std::vector<std::string> ans;
  while(!(h == 0 && w == 0)){
    int color=-1, orient, leftX, leftY;
    int sx, sy, gx, gy;
    std::cin >> sx >> sy >> gx >> gy;
    std::vector<std::vector<int>> board(h + 2, std::vector<int>(w + 2, 0));
    std::vector<std::vector<bool>> canGo(h + 2, std::vector<bool>(w + 2, false));
    std::cin >> n;
    int start = -1, goal = -1;
    for (int i = 0; i < n; i++) {
      std::cin >> color >> orient >> leftX >> leftY;
 
 
      if (orient == 0) {
        for (int j = 0; j <= 3; j++) {
          for (int k = 0; k <= 1; k++) {
            board[leftY + k][leftX + j] = color;
            if (leftX + j == sx && leftY + k == sy) {
              start = color;
            }
            else if (leftX + j == gx && leftY + k == gy) {
              goal = color;
            }
          }
        }
 
      }
      else {
        for (int j = 0; j <= 1; j++) {
          for (int k = 0; k <= 3; k++) {
            board[leftY + k][leftX + j] = color;
            if (leftX + j == sx && leftY + k == sy) {
              start = color;
            }
            else if (leftX + j == gx && leftY + k == gy) {
              goal = color;
            }
          }
        }
      }
    }

    // for (int i = 0; i <= h; i++) {
    //   for (int j = 0; j <= w; j++) {
    //     std::cerr << board[i][j] << " ";
    //   }
    //   std::cerr << std::endl;
    // }
    
    if (start != -1) {
      for (int i = 0; i <= h; i++) {
        for (int j = 0; j <= w; j++) {
          if (board[i][j] == start) {
            canGo[i][j] = true;
          }
        }
      }
    }

    if (start != goal || start == -1) {
      ans.push_back("NG");
      std::cin >> w >> h;
      continue;
    }

    bool result = dfs(sx, sy, gx, gy, canGo);
    if (result) { ans.push_back("OK"); }
    else { ans.push_back("NG"); }
    std::cin >> w >> h;
  }
  int anssize = ans.size();
  for (int i = 0; i < anssize; i++) {
    std::cout << ans[i] << std::endl;
  }
  return 0;
}

C++: #include<stdio.h>
int main(void)
{
	int w,h;
	int map[101][101];
	int st[2],go[2];
	int i,j,k;
	int num;
	int b_c,b_ang,b_x,b_y;
	int sign;
	int ans;
	
	for(;;)
	{
		ans=0;
		
		for(i=0;i<100;i++)
		{
			for(j=0;j<100;j++)
				map[i][j]=0;
		}
		
		scanf("%d%d",&w,&h);
		
		if(w==0 && h==0)
			break;
		
		scanf("%d%d%d%d",&st[0],&st[1],&go[0],&go[1]);
		
		
		scanf("%d",&num);
		
		for(i=0;i<num;i++)
		{
			scanf("%d%d%d%d",&b_c,&b_ang,&b_x,&b_y);
			
			if(b_ang==0)
			{
				for(j=0;j<4;j++)
				{
					for(k=0;k<2;k++)
						map[b_x+j][b_y+k]=b_c;
				}
			}
			else
			{
				for(j=0;j<4;j++)
				{
					for(k=0;k<2;k++)
						map[b_x+k][b_y+j]=b_c;
				}
			}
		}
		
		if(map[st[0]][st[1]]==0 || map[go[0]][go[1]]==0)
			printf("NG\n");
		else
		{
			sign=map[st[0]][st[1]];
			
			for(i=0;i<w;i++)
			{
				for(j=0;j<h;j++)
				{
					if(map[i][j]!=sign)
						map[i][j]=0;
				}
			}
			
			map[st[0]][st[1]]=-1;
			map[go[0]][go[1]]=-2;
			
			for(i=st[0],j=st[1];;)
			{
				if(map[i+1][j]==-2 || map[i][j+1]==-2 || map[i-1][j]==-2 || map[i][j-1]==-2)
				{
					ans=1;
					break;
				}
				else if(map[i-1][j]!=0 && map[i][j-1]!=0 && map[i+1][j]!=0 && map[i][j+1]!=0)
				{
					if(map[i+1][j]==sign)
					{
						map[i][j]=7;
						i++;
					}
					else if(map[i][j+1]==sign)
					{
						map[i][j]=7;
						j++;
					}
					else if(map[i-1][j]==sign)
					{
						map[i][j]=7;
						i--;
					}
					else if(map[i][j-1]==sign)
					{
						map[i][j]=7;
						j--;
					}
				}
				else if(map[i+1][j]!=sign && map[i][j+1]==sign)//ツ可コ
				{
					map[i][j]=7;
					j++;
				}
				else if(map[i+1][j]!=sign && map[i][j-1]==sign)//ツ湘」
				{
					map[i][j]=7;
					j--;
				}
				else if(map[i-1][j]!=sign && map[i][j+1]==sign)//ツ可コ
				{
					map[i][j]=7;
					j++;
				}
				else if(map[i-1][j]!=sign && map[i][j-1]==sign)//ツ湘」
				{
					map[i][j]=7;
					j--;
				}
				else if(map[i+1][j]==sign/* && map[i][j-1]!=sign*/)//ツ右
				{
					map[i][j]=7;
					i++;
				}
				else if(map[i-1][j]==sign/* && map[i][j+1]!=sign*/)//ツ債カ
				{
					map[i][j]=7;
					i--;
				}
				else if(map[i+1][j]!=sign && map[i][j+1]!=sign && map[i-1][j]!=sign && map[i][j-1]!=sign)
				{
					ans=2;
					break;
				}
			}
			if(ans==1)
				printf("OK\n");
			else if(ans==2)
				printf("NG\n");
		}
	}
}