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 <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <complex>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-9
#define INF 2000000000
#define sz(x) ((int)(x).size())
#define fi first
#define sec second
#define SORT(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define EQ(a,b) (abs((a)-(b))<eps)
int w,h;
int sx,sy,gx,gy;
int n;
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};
bool used[120][120];
int f[120][120];
void set(int c,int d,int x,int y)
{
	if(d==0)
	{
		for(int i=0;i<2;i++)
		{
			for(int j=0;j<4;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	else
	{
		for(int i=0;i<4;i++)
		{
			for(int j=0;j<2;j++)
			{
				f[x+i][y+j]=c;
			}
		}
	}
	return;
}
bool judge()
{
	if(f[sx][sy]!=f[gx][gy])return false;
	memset(used,false,sizeof(used));
	queue<P> q;
	q.push(mp(sx,sy));
	used[sx][sy]=true;
	while(!q.empty())
	{
		P a=q.front();
		q.pop();
		for(int i=0;i<4;i++)
		{
			int nx=a.fi+dx[i],ny=a.sec+dy[i];
			if(nx<0||nx>=w||ny<0||ny>=h)continue;
			if(used[nx][ny]||f[nx][ny]!=f[a.fi][a.sec])continue;
			if(nx==gx&&ny==gy)return true;
			used[nx][ny]=true;
			q.push(mp(nx,ny));
		}
	}
	return false;
}
int main()
{
	while(1)
	{
		scanf("%d %d",&h,&w);
		if(w==0&&h==0)break;
		scanf("%d %d",&sy,&sx);
		scanf("%d %d",&gy,&gx);
		scanf("%d",&n);
		for(int i=0;i<n;i++)
		{
			int c,d,x,y;
			scanf("%d %d %d %d",&c,&d,&y,&x);
			set(c,d,x,y);
		}
		if(judge())puts("OK");
		else puts("NG");
	}
	return 0;
}

C++: #include <cstring>
#include <iostream>
using namespace std;
const int MAX_WH = 100;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};

int w, h;
int sx, sy, gx, gy;
int col;
int field[MAX_WH + 1][MAX_WH + 1];

bool solve(int x, int y) {
	if (x == gx && y == gy) return true;
	field[x][y] = -1;
	for (int i = 0; i < 4; i++) {
		int nextX = x + dx[i];
		int nextY = y + dy[i];
		if (0 < nextX && nextX <= w && 0 < nextY && nextY <= h && col == field[nextX][nextY]) {
			if (solve(nextX, nextY)) return true;
		}
	}
	return false;
}

int main () {
	while (cin >> w >> h, w || h) {
		memset(field, 0, sizeof(field));
		cin >> sx >> sy >> gx >> gy;
		int n;
		cin >> n;
		for (int i = 0; i < n; i++) {
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			if (d == 0) {
				for (int i = 0; i < 2; i++) {
					for (int j = 0; j < 4; j++) {
						field[x + j][y + i] = c;
					}
				}
			}
			else {
				for (int i = 0; i < 4; i++) {
					for (int j = 0; j < 2; j++) {
						field[x + j][y + i] = c;
					}
				}
			}
		}
		col = field[sx][sy];
		cout << (solve(sx, sy) ? "OK" : "NG") << endl;
	}
	return 0;
}

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



typedef vector<vector<int> > Matrix;
int w,h,xs,ys,xg,yg,n,color;
string res = "NG";
void write(Matrix &board,int c, int d, int x, int y){
  int width,length;
  if(d == 0){ width = 4; length =2; }
  if(d == 1){ width = 2; length =4; }
  for(int i=0; i<width; ++i){
    for(int j=0; j<length; ++j)
      board[x+i][y+j]=c;
  }
}
void func(Matrix &board,int nx,int ny){
  if(board[nx][ny] == 0){
    res = "NG";
    return;
  }
  if( nx==xg && ny==yg){
    res = "OK";
    return;
  }
  board[nx][ny] = 0;
  if( 0<=nx-1 && color==board[nx-1][ny])
    func(board,nx-1,ny);
  if( 0<=ny-1 && color==board[nx][ny-1])
    func(board,nx,ny-1);
  if( nx+1<=w && color==board[nx+1][ny])
    func(board,nx+1,ny);
  if( ny+1<=h && color==board[nx][ny+1])
    func(board,nx,ny+1);
}


int main(void){
  int c,d,x,y;
  while(cin >> w >> h,w||h){

    if( w==0 && h==0) return 0;
    cin >> xs >> ys >> xg >> yg >> n;
    xs--; ys--; xg--; yg--;
    Matrix board(w, vector<int>(h,0));
    for(int i=0; i<n; ++i){
      cin >> c >> d >> x >> y;
      --x; --y;
      write(board,c,d,x,y);
    }
    color = board[xs][ys];
    func(board,xs,ys);
    cout << res << endl;
    board.clear();
  }
  return 0;
}

C++: #include <iostream>
#include <utility>
#include <vector>
#include <cstring>
using namespace std;
#define MAX 100

struct in {
	int c;
	int d;
	pair<int, int> p;
};

int dx[] = { 1, 0, -1, 0 };
int dy[] = { 0, 1, 0, -1 };
int w, h, n;
pair<int, int> st, gl;
int map[MAX+2][MAX+2];//map[X][Y]
vector<in> info;
bool f;

bool dfs(int x, int y, int c) {
	if (map[x][y] != c) return false;
	map[x][y] = -1;
	if (x==gl.first&&y==gl.second) return true;
	for (int i=0; i<4; i++) {
		if (x+dx[i]<0 || y+dy[i]<0 || x+dx[i]>=w+2 || y+dy[i]>=h+2) continue;
		if (dfs(x+dx[i], y+dy[i], c)) return true;
	}

	return false;
}

int main() {
	while (cin >> w >> h, w||h) {
		cin >> st.first >> st.second >> gl.first >> gl.second >> n;
		info.clear();
		for (int i=0; i<n; i++) {
			in t;
			cin >> t.c >> t.d >> t.p.first >> t.p.second;
			info.push_back(t);
		}

		memset(map, 0, sizeof(map));
		for (int i=0; i<n; i++) {
			int W=4, H=2;
			if (info[i].d) { int t=W; W=H; H=t; }
			for (int x=0; x<W; x++)
			for (int y=0; y<H; y++)
				map[info[i].p.first+x][info[i].p.second+y] = info[i].c;
		}

		cout << ((dfs(st.first, st.second, map[st.first][st.second])) ? "OK" : "NG") << endl;
	}
	return 0;
}