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<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define it ::iterator
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double ESP=1e-10;
const int inf=100000;
using namespace std;
int sx,sy,gx,gy,col;
void func(vector<vector<int> >out,vector<vector<bool> >&out2,int x,int y){
  out2[x][y]=true;
  loop(i,-1,2)loop(j,-1,2){
    if(out[x+i][y+j]==inf)continue;
    if(out2[x+i][y+j]!=true&&out[x+i][y+j]==col)func(out,out2,x+i,y+j);
  }
}
int main(){
  int n,m;
  while(cin>>m>>n,n|m){
    cin>>sx>>sy>>gx>>gy;
    int nn;cin>>nn;
    vector<vector<int> >out(n+2);
    vector<vector<bool> >out2(n+2);
    rep(i,n+2)rep(j,m+2){
      if(i==0||i==n+1||j==0||j==m+1)out[i].pb(inf);
      else out[i].pb(0);
    }
    rep(i,n+2)rep(j,m+2)out2[i].pb(false);
    rep(q,nn){
      int a,b,c,d;
      cin>>a>>b>>d>>c;
      if(b)rep(i,4)rep(j,2)out[i+c][j+d]=a;
      else rep(i,2)rep(j,4)out[i+c][j+d]=a;
    }/*
    cout<<endl;
    rep(i,n+2){
      rep(j,m+2)cout<<" "<<out[i][j];
      cout<<endl;
      }*/
    
    if(out[gx][gy]==0||out[gx][gy]!=out[sx][sy]||out[sx][sy]==0){
      cout<<"NG"<<endl;
      continue;
    }
    col=out[sx][sy];
    func(out,out2,sx,sy);
    if(out2[gx][gy])cout<<"OK"<<endl;
    else cout<<"NG"<<endl;
    /*rep(i,n){
      rep(j,m)cout<<" "<<out[i+1][j+1];
      cout<<endl;
      }*/
  }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>
#include <fstream>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define MOD 1000000007
#define EPS 1e-10
#define MAX_N 100100
#define MAX_M 100100

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;
typedef pair<P, char> PC;
typedef pair<int, string> PSI;

int w, h, sx, sy, gx, gy;
int n, c, d, x, y;

int table[110][110];
int dis[110][110];

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

void solve(){
	REP(i, 110)REP(j, 110)dis[i][j] = INF;
	dis[sy][sx] = 0;

	queue<P> que;
	que.push(P(sy, sx));

	while (que.size()){
		P p = que.front(); que.pop();
		int cx = p.second, cy = p.first;

		if (y == gy&&x == gx)break;

		REP(i, 4){
			int nx = cx + dx[i], ny = cy + dy[i];
			if (nx >= 0 && nx < w&&ny >= 0 && ny < h){
				if (table[ny][nx] == table[cy][cx]
					&&dis[ny][nx] == INF){
					dis[ny][nx] = dis[cy][cx] + 1;
					que.push(P(ny, nx));
				}
			}
		}
	}
}

int main(){
	while (cin >> w >> h&&w + h){
		REP(i, 110)REP(j, 110){
			table[i][j] = 0;
		}
		cin >> sx >> sy >> gx >> gy;
		sx--;
		sy--;
		gx--;
		gy--;

		cin >> n;
		REP(i, n){
			cin >> c >> d >> x >> y;
			x--;
			y--;
			if (d == 0){
				REP(i, 2){
					REP(j, 4){
						table[y + i][x + j] = c;
					}
				}
			}
			else{
				REP(i, 4){
					REP(j, 2){
						table[y + i][x + j] = c;
					}
				}
			}
		}

		solve();

		if (dis[gy][gx] != INF&&table[sy][sx] != 0 && table[gy][gx] != 0)cout << "OK" << endl;
		else cout << "NG" << endl;
	}
}

C++: #include <iostream>
using namespace std;
 
int weight, hight;
int g[101][101];
int sc;
int sx, sy, gx, gy;
bool flag = false;
const int vx[4] = {0, 0, 1, -1};
const int vy[4] = {1, -1, 0, 0};
 
void dfs(int x, int y){
    if(x == gx && y == gy){
        flag = true;
        return;
    }
    
    if(g[y][x] != sc){
        flag = false;
        return;
    }
    
    g[y][x] = -1;
    
    for(int i = 0;i < 4;i++){
        int nx = x + vx[i];
        int ny = y + vy[i];
         
        if(nx >= 0 && nx < weight && ny >= 0 && ny < hight && g[ny][nx] == sc){
            dfs(nx, ny);
        }
    }
    return;
}
 
int main(){
    while(1){
        int n, c, d, x, y;
        flag = false;
        g[101][101] = {};
        
        cin >> weight >> hight;
 
        if(weight == 0 && hight == 0){
            break;
        }
         
        cin >> sx >> sy >> gx >> gy >> n;
         
        for(int i = 0;i < n;i++){
            cin >> c >> d >> x >> y;
             
            if(d == 0){
                for(int h = 0;h < 2;h++){
                    for(int w = 0;w < 4;w++){
                        g[y+h][x+w] = c;
                    }
                }
            }else{
                for(int h = 0;h < 4;h++){
                    for(int w = 0;w < 2;w++){
                        g[y+h][x+w] = c;
                    }
                }
            }
        }
         
        sc = g[sy][sx];
        dfs(sx, sy);
         
        if(flag){
            cout << "OK" << endl;
        }else{
            cout << "NG" << endl;
        }
    }
     
    return 0;
}