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



typedef vector<vector<int> > Matrix;
int w,h,xs,ys,xg,yg,n,flag;

class Block{
public:
  int color;
  int direction;
  int x,y,dx,dy;
  void write(Matrix &board){
    if(direction == 0)
      dx = 4,dy = 2;
    else if(direction == 1)
      dx = 2,dy = 4;
    for(int i=0; i<dx; ++i){
      for(int j=0; j<dy; ++j){
	(board.at(x+i-1)).at(y+j-1) = color;
      }
    }
  }
};
  
void func(Matrix &board,int nx,int ny){
  if( nx==xg && ny==yg) flag = 1;
  else if( w<=nx+1 || h<=ny+1) return;
  if(board[nx-1][ny-1]==board[nx][ny-1])
    func(board,nx+1,ny);
  if(board[nx-1][ny-1]==board[nx-1][ny])
    func(board,nx,ny+1);
}


int main(void){
  string res;
  while(1){
    cin >> w >> h;
    if( w==0 && h==0) return 0;
    cin >> xs >> ys >> xg >> yg >> n;
    Block *object;
    object = new Block[n];
    Matrix board(w, vector<int>(h,0));
    for(int i=0; i<n; ++i){
      cin >> object[i].color;
      cin >> object[i].direction;
      cin >> object[i].x;
      cin >> object[i].y;
      object[i].write(board);
    }
    func(board,xs,ys);
    if(flag==1) res = "OK";
    else res = "NG";
    cout << res << endl;
    flag = 0;
    delete[] object;
    board.clear();
  }
}

C++: #include<iostream>
#include<algorithm>
#include<string>
	using namespace std;
	int xs,ys,w,h,n,ban[111][111],xg,yg;bool visited[101][101];
	bool dfs(int x,int y,int c){
		//cout<<x<<" "<<y<<endl;
		if(xg==x&&yg==y)return true;
		if(x==xs&&ys==y&&ban[x][y]==-1||ban[x][y]!=c)return false;
		//if(ban[xs][ys]==0)return false;
		if(ban[x+1][y]==ban[xs][ys]&&visited[x][y]==false){
			visited[x][y]=true;
			if(dfs(x+1,y,c))return true;
		}
		if(ban[x][y+1]==ban[xs][ys]&&visited[x][y]==false){
			visited[x][y]=true;
			if(dfs(x,y+1,c))return true;
		}
		if(x>=2&&ban[x-1][y]==ban[xs][ys]&&visited[x][y]==false){
			visited[x][y]=true;
			if(dfs(x-1,y,c))return true;
		}
		if(y>=2&&ban[x][y-1]==ban[xs][ys]&&visited[x][y]==false){
			visited[x][y]=true;
			if(dfs(x,y-1,c))return true;
		}
		return false;
	}


int main(){

	while(cin>>w>>h&&w&&h){
	cin>>xs>>ys>>xg>>yg>>n;
	for(int i=0;i<101;i++)
	for(int j=0;j<101;j++)ban[i][j]=-1,visited[i][j]=false;
	
	for(int i=0;i<n;i++){
		int c,d,x,y;
		cin>>c>>d>>x>>y;
		if(!d){
			for(int i=x;i<x+4;i++){
				for(int j=y;j<y+2;j++){
					ban[i][j]=c;
				}
			}
		}
		else{
		for(int i=x;i<x+2;i++){
				for(int j=y;j<y+4;j++){
					ban[i][j]=c;
				}
			}
		}
		}
		if(dfs(xs,ys,ban[xs][ys]))cout<<"OK"<<endl;
	else cout<<"NG"<<endl;
	}
	return 0;
	}

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

int F[102][102];

void setblock(int c, int d, int x, int y){
  if(d==0){
    for(int i=0;i<4;i++){
      F[y][x+i]=c;
      F[y+1][x+i]=c;
    }
  }else{
    for(int i=0;i<4;i++){
      F[y+i][x]=c;
      F[y+i][x+1]=c;
    }
  }

}

void DFS(int Y, int X, int c){
  if(F[Y][X]!=c)
    return;

  F[Y][X] = 6;

  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(true){
  cin >> w >> h;
  if(w==0&&h==0){
    break;
  }
  cin >> xs >> ys;
  cin >> xg >> yg;
  cin >> n;
  for(int i=0; i<n; i++){
    int c,d,x,y;
    cin >> c >> d >> x >> y;
    setblock(c,d,x,y);
  }

}

  int S=F[ys][xs];
  DFS(xs,ys,F[ys][xs]);
  if(F[ys][xs]==6){
    cout << "OK" << endl;
  }else{
    cout << "NO" << endl;
  }

  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;

typedef pair<int,int> P;
const int MAX = 101;

int maze[MAX][MAX];
bool come[MAX][MAX];
P s,g;
int W,H,c;
int dx[4] = {1,0,0,-1};
int dy[4] = {0,1,-1,0};

void init(){
  memset(come,false,sizeof(come));
  memset(maze,0,sizeof(maze));
}


void input_B(){
  int n;
  cin >> n;
  while(n--){
    int c,d,x,y;
    cin >> c >> d >> x >> y;
    if(d){
      for(int i = y; i < y+4; i++)
	for(int j = x; j < x+2; j++)
	  maze[i][j] = c;
    }else{
      for(int i = y; i < y+2; i++)
	for(int j = x; j < x+4; j++)
	  maze[i][j] = c;
    }
  }
}


void solve(P p){
  
  if(come[p.second][p.first] == false){
    come[p.second][p.first] = true;
    for(int i = 0; i < 4; i++)
      if(0 < p.first+dx[i] && p.first+dx[i] <= W &&
	 0 < p.second+dy[i] && p.second+dy[i] <= H &&
	 maze[p.second][p.first] == c) solve(P(p.first+dx[i],p.second+dy[i]));
  }
}

void print(){
  for(int i = 1; i < H; i++){
    for(int j = 1; j < W; j++)// cout << come[i][j];
      cout << maze[i][j];
    cout << endl;
  }

}


int main(){
  while(cin >> W >> H && W+H){
    init();
    cin >> s.first >> s.second;
    cin >> g.first >> g.second;
    input_B();
    c = maze[s.second][s.first];
    solve(s);
    //print();
    if(come[g.second][g.first] && c) cout << "OK" << endl;
    else cout << "NG" << endl;
  }
  return 0;
}