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 <string>
#include <queue>
using namespace std;

typedef pair<int, int> P;


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

void put_b(int a[][105]) {
  int X, Y;
  if(d == 0) X = 4, Y = 2;
  else X = 2, Y = 4 ;
  for(int i = 0; i < Y; i++)
    for(int j = 0; j < X; j++)
      a[y + i][x + j] = c;
}

bool bfs(int a[][105]) {
  int cs = a[ys][xs];
  if(cs != a[yg][xg]) return false;

  //cout << ys << xs << endl;
  queue<P> que;
  que.push(P(xs, ys));
  while(que.size()) {
    P p = que.front();
    que.pop();
    if(p.first == xg && p.second == yg) return true;
    for(int i = 0; i < 4; i++) {
      int nx = p.first + dx[i], ny = p.second + dy[i];
      if(0 < nx && nx <= w && 0 < ny && ny <= h && a[ny][nx] == cs) {
	que.push(P(nx, ny));
	a[ny][nx] = 0;
      }
    }
  }
  return false;
}
int main() {
  while(cin >> w >> h, w != 0 || h != 0) {
    int a[105][105] = {};
    cin >> xs >> ys;
    cin >> xg >> yg;
    cin >> n;
  
    while(n--) {
      cin >> c >> d >> x >> y;
      put_b(a);
    }
    /*
     for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++)
      cout << a[i][j];
      cout << endl;
      }
    */
    if(bfs(a) == true) cout << "OK" << endl;
    else cout << "NG" << endl;
  }
  return 0;
}

C++: #include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string toStr(T x) { ostringstream sout; sout << x; return sout.str();}
typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n) FOR(i,0,(n)-1)
const double EPS = 1e-12;
const double PI = acos(-1.0);
const int INF = INT_MAX/10;

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

struct state {
	int x, y;
	state(int x, int y) : x(x), y(y) {};
};

int main() {
	int w, h;
	while(cin >> w >> h, w) {
		vvi field(h+1, vi(w+1));
		vvi visit(h+1, vi(w+1));
		
		int xs, ys, xg, yg, n;
		cin >> xs >> ys >> xg >> yg >> n;

		int c, d, x, y;
		REP(i, n) {
			cin >> c >> d >> x >> y;
			REP(j, 4) {
				REP(k, 2) {
					if(d) {
						field[y+j][x+k] = c;
					} else {
						field[y+k][x+j] = c;
					}
				}
			}
		}

		stack<state> S;
		S.push(state(xs, ys));
		int color = field[ys][xs];
		bool goal = false;
		while(!S.empty()) {
			state st = S.top();
			S.pop();

			if(st.x == xg && st.y == yg) {
				goal = true;
				break;
			}

			int nx, ny;
			REP(d, 4) {
				nx = st.x + dx[d];
				ny = st.y + dy[d];
				if(0<=nx && nx<w && 0<=ny && ny<h) {
					if(!visit[ny][nx] && field[ny][nx] == color) {
						visit[ny][nx] = 1;
						S.push(state(nx, ny));
					}
				}

			}
		}

		if(goal) {
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
	}
}

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

int a[200][200],color;

void dfs(int x,int y){
  
  if(x < 102 && y < 102){
  
    a[y][x] = 9;
    
    if(a[y+1][x] == color){
      dfs(x,y+1);
    }
    if(a[y][x+1] == color){
      dfs(x+1,y);
    }
    if(a[y-1][x] == color){
      dfs(x,y-1);
    } 
    if(a[y][x-1] == color){
      dfs(x-1,y);
    }
  
  }

} 

int main(){

  int xs,ys,xg,yg,n,c,d,x,y,w,h;

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

    for(int i = 0 ; i < 102 ; i++){
      for(int j = 0 ; j < 102 ; j++){
	a[i][j]=0;
      }
    }

    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 i = 0 ; i < 2 ; i++){
	  for(int j = 0 ; j < 4 ; j++){
	    a[i+y][j+x] = c;
	  }
	}
      }else{
	for(int i = 0 ; i < 4 ; i++){
	  for(int j = 0 ; j < 2 ; j++){
	    a[i+y][j+x] = c;
	  }
	}
      }
    
    }
    
    /*
      for(int i = 0 ; i < h+2 ; i ++){
      for(int j = 0 ; j < w+2 ; j++){
      cout << a[i][j];
      }
      cout <<endl;
      }
      cout <<endl;
    */
    
    color = a[ys][xs];
    dfs(xs,ys);
    
    /*
      for(int i = 0 ; i < h+2 ; i ++){
      for(int j = 0 ; j < w+2 ; j++){
      cout << a[i][j];
      }
      cout <<endl;
      }
    */
    
    if(a[yg][xg] == 9){
      cout <<"OK"<<endl;
    }else{
      cout <<"NG"<<endl;
    }
    
  }      
  
  return 0;
  
}