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;

char F[102][102];
void DFC(int y,int x);
void block_set(int c,int d,int x,int y);
int cs;
int xg,yg;
bool result = false;

int main(){
  int H,W;
  while(1){
    result = false;
    cin >> H >> W;
    if(H==0&&W==0)
      break;
    int xs,ys;
    cin >> xs >> ys >> xg >> yg;
    int n;
    cin >> n;
    int c,d,x,y;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      if(i==0)
        cs = c;
        block_set(c,d,x,y);
    }

    DFC(xs,ys);

    if(result)
      cout << "YES" << endl;
      else
      cout << "NO" << endl;
  }

  return 0;
}

void DFC(int x,int y){
  if(F[x][y]!=cs)
    return;

  if(x==xg,y==yg)
    result = true;

  F[x][y]=0;

  DFC(x-1,y);
  DFC(x+1,y);
  DFC(x,y-1);
  DFC(x,y+1);
}

void block_set(int c,int d,int x,int y){
  for(int i=0;i<2;i++){
    for(int j=0;j<4;j++){
      if(d){
        F[x+i][y+j] = c;
      }
      else{
        F[x+j][y+i] = c;
      }
    }
  }
}

C++: int board[101][101];
int xg , yg;
int w, h;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
int sc;
bool b;

void dfs(int x , int y){
	if(x==xg&&y==yg) {b=true;return;}
	for(int i=0;i<4;++i){
		int tx=x+dx[i];
		int ty=y+dy[i];
		if(tx<=0||ty<=0||tx>w||ty>h) continue;
		if(board[tx][ty]!=sc || board[tx][ty]==0) continue;
		if(b) continue;
		dfs(tx,ty);
	}
}

int main(){
	while(cin >> w >> h , w||h){
		int xs , ys;
		int n;
		b=false;
		memset(board,0,sizeof(board));
		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 k=0;k<2;++k){
					for(int j=0;j<4;++j){
						board[x+j][y+k]=c;
					}
				}
			} else if(d==1){
				for(int k=0;k<4;++k){
					for(int j=0;j<2;++j){
						board[x+j][y+k]=c;
					}
				}
			}
		}
		sc=board[xs][ys];
		int gc=board[xg][yg];
		if(sc!=gc) {}
		else dfs(xs,ys);
		cout << ( b ? "OK" : "NG") << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

int h,w;
int maps[100][100];
int color;
int gy,gx,sy,sx;
int dy[]={-1,0,1,0};
int dx[]={0,-1,0,1};
int muki[2][2]={
  {2,4},
  {4,2}
};
    
  

bool dfs(int y,int x);

int main(){
  int n;
  int c,d,y,x;
  while(cin >> w >> h,w | h){
    memset(maps,-1,sizeof(maps));
    cin >> sx >> sy >> gx >> gy;
    sx--;sy--;gx--;gy--;
    cin >> n;
    for(int i = 0; i < n; ++i){
      cin >> c >> d >> x >> y;
      y--;x--;
      for(int j = 0; j < muki[d][0]; j++){
	for(int k = 0;k < muki[d][1]; k++){
	  maps[y + j][x + k] = c;
	}
      }
    }
    for(int i=0;i<h;i++){
      for(int j = 0; j< w ; j++){
	if(i==sy && j == sx)color = maps[sy][sx];
      }
    }
    /*
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	printf("%3d",maps[i][j]);
      }
      cout<<endl;
    }*/

    if(dfs(sy,sx))cout << "OK" << endl;
    else cout << "NG" << endl;
    
    /*
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	printf("%3d",maps[i][j]);
      }
      cout<<endl;
      }*/

  }
}
 
bool dfs(int y,int x){
  maps[y][x] = -1;
  if(gy==y && gx==x){
    return true;
  }
  bool b = false;
  for(int i=0;i<4;i++){
    int vy=y+dy[i];
    int vx=x+dx[i];
    if(vy >= 0 && vy < h && vx >= 0 && vx < w && maps[vy][vx] != -1 && maps[vy][vx] == color){
      b = b | dfs(vy,vx);
    }
  }
  return b;
}

C++: #include<iostream>
#include<string>
#include<string.h>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<stdlib.h>
#include<queue>
#include<map>
#include<vector>
#include<list>
#include<stack>
#include<functional>

using namespace std;

#define all(c) (c).begin(), (c).end()
#define rep(i,n) for(int i=0;i<n;i++)

typedef unsigned long long ull; typedef long long ll;

const int INF=100000000; int dx[4]={1,0,-1,0}; int dy[4]={0,1,0-1};

typedef pair<int ,int > P;

char maze[105][105];

int sx,sy; int gx,gy; int w,h;

char sc; //スタート地点のカラー

//stdin //stdout

void dfs(int x,int y) { maze[x][y]='9';

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 &&maze[nx][ny]==sc) { dfs(nx,ny); }

} return ; }

void solve() {

rep(i,101) rep(j,101) maze[i][j]='0';

int n; char c; int d; int x,y;

cin>>sy>>sx; cin>>gy>>gx;

cin>>n;

rep(i,n) { cin>>c>>d>>x>>y;

if(d==1) { rep(i,4) { rep(j,2) { maze[x+i][y+j]=c;

} } } else if (d==0) { rep(i,2) { rep(j,4) { maze[x+i][y+j]=c;

} } }

} //6 6 //1 1 //3 6 //2 //1 0 1 1 //1 1 3 3 // rep(i,w+1) // { // rep(j,h+1) // { // cout<<maze[i][j]; //// } // cout<<endl; // } //// cout<<maze[gx][gy]<<endl;

if(maze[sx][sy]=='0') { cout<<"NG"<<endl; return; } else { sc=maze[sx][sy]; dfs(sx,sy); }

//rep(i,w+1) //{ // rep(j,h+1) // { // cout<<maze[i][j];

// } // cout<<endl; //}

if(maze[gx][gy]=='9') { cout<<"OK"<<endl; return; } else { cout<<"NG"<<endl; return; }

}

int main() {

while(cin>>w>>h) { if(w==0 && h==0) { return 0; } else { solve(); } }

return 0; }