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 <bits/stdc++.h>

using namespace std;

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

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

int w, h;
int xs, ys;
int xg, yg;
int maze[102][102];

using P = pair<int, int>;
void solve() {
    int c = maze[ys][xs];
    queue<P> que;
    que.push(P(ys, xs));
    set<P> visited;
    visited.insert(P(ys, xs));
    bool ok = false;
    while (que.size()) {
        auto p = que.front();
        que.pop();
        int y = p.first;
        int x = p.second;
        if (yg == y && xg == x) ok = true;
        rep(k, 4) {
            int ny = y + dy[k];
            int nx = x + dx[k];
            if (ny < 0 || nx < 0) continue;
            if (h <= ny || w <= nx) continue;
            if (maze[ny][nx] != c) continue;
            if (visited.count(P(ny, nx))) continue;
            visited.insert(P(ny, nx));
            que.push(P(ny, nx));
        }
    }
    cout << (ok ? "OK" : "NG") << endl;
}

int main() {
    while (cin >> w >> h, w) {
        rep(i, 102) rep(j, 102) maze[i][j] = -1;
        cin >> xs >> ys;
        cin >> xg >> yg;
        int n;
        cin >> n;
        rep(i, n) {
            int c, d, x, y;
            cin >> c >> d >> x >> y;
            if (d == 0) {
                rep(i, 2) rep(j, 4) maze[y + i][x + j] = c;
            } else {
                rep(i, 4) rep(j, 2) maze[y + i][x + j] = c;
            }
        }
        solve();
    }

    return 0;
}

C++: #include<bits/stdc++.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define pb(a) push_back(a)
#define all(a) (a).begin(), (a).end()
#define debug(x) cout << "debug " << x << endl;
using namespace std;

int w, h, xs, ys, xg, yg, n, c, d, x, y, b[101][101];
int dx[] = {0, -1, 0, 1}, dy[] = {-1, 0, 1, 0};

bool dfs(int x, int y){
    int nx, ny;
    b[x][y] = 0;
    if(x == xg && y == yg) return true;
    bool r = 0;
    rep(i, 4){
        nx = x + dx[i]; ny = y + dy[i];
        if(nx > 0 && nx <= h && ny > 0 && ny <= w && b[nx][ny]==c)r=r||dfs(nx, ny);
    }
    return r;
}

int main(){
    while(cin >> w >> h, w||h){
        memset(b, 0, sizeof(b));
        cin >> ys >> xs >> yg >> xg >> n;
        rep(i,n){
            int c, d, x, y;
            cin >> c >> d >> y >> x;
            rep(j, (d?4:2)) rep(k, (d?2:4)) b[x + j][y + k] = c;
        }
        c = b[xs][ys];

        if(c > 0 && dfs(xs, ys)) cout << "OK" << endl;
        else cout << "NG" << endl;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <utility>
#include <string>

#define Pa pair<int,int>

using namespace std;

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

string bfs(int a[101][101], int sx, int sy, int gx, int gy, int w, int h)
{
	int s, t, m = a[sy][sx];
	bool vis[101][101];
	string str = "NG";
	queue<Pa> que;
	Pa pa;
	fill(&vis[0][0], &vis[h+1][w+1], true);
	
	que.push(Pa(sy, sx));
	vis[sy][sx] = false;
	
	while(!que.empty()){
		pa = que.front();
		que.pop();
		if(pa.first == gy && pa.second == gx){
			str = "OK";
			break;
		}
		
		for(int i = 0; i < 4; i++){
			s = pa.first + dy[i];
			t = pa.second + dx[i];
			if(1 <= s && s <= h && 1 <= t && t <= w){
				if(vis[s][t] && m == a[s][t]){
					que.push(Pa(s, t));
					vis[s][t] = false;
				}
			}
		}
	}
	
	return str;
}

int main()
{
	int a[101][101], w, h, sx, sy, gx, gy, s, t, u, v, n;
	
	while(1){
		cin >> w >> h;
		if(w == 0 && h == 0){
			break;
		}
		fill(&a[0][0], &a[h+1][w+1], 0);
		cin >> sx >> sy;
		cin >> gx >> gy;
		cin >> n;
		
		while(n--){
			cin >> s >> t >> u >> v;
			if(t == 0){
				for(int i = v; i <= v+1; i++){
					for(int j = u; j <= u+3; j++){
						a[i][j] = s;
					}
				}
			} else {
				for(int i = v; i <= v+3; i++){
					for(int j = u; j <= u+1; j++){
						a[i][j] = s;
					}
				}
			}
		}
		
		cout << bfs(a, sx, sy, gx, gy, w, h) << endl;
	}
	
	return 0;
}

C++: #include<iostream>
#include<queue>
#define MAX 100
using namespace std;

int map[MAX+2][MAX+2];
bool check[MAX+2][MAX+2];
int dx[4] = { -1,1,0,0};
int dy[4] = { 0,0,-1,1};

int main () {

  while ( true ) {

    queue<int> next;

    while( !next.empty() ) {
      next.pop();
    }
    
    int w,h;
    cin >> w >> h ;

    if ( w == 0 )
      break;

    int xs,ys;
    cin >> xs >> ys;
    
    int xg, yg;
    cin >> xg >> yg;

    int n;
    cin >> n;

    int c,d,x,y;

    for ( int i=0; i<MAX+2; i++ ) {
      for ( int j=0; j<MAX+2; j++ ) {
	map[i][j] = 0;
	check[i][j] = true;
      }
    }

    for ( int i=0; i<n; i++ ) {
      cin >> c >> d >> x >> y;
      
      //int count = 0;
      for ( int j=0; j<2; j++ ) {
	for ( int k=0; k<4; k++ ) {
	  //cout << count;
	  if ( d == 0 ) {
	    map[y+j][x+k] = c;
	  } else {
	    map[y+k][x+j] = c;
	  }
	}
      }
      //cout << endl;
    }

    next.push(y*1000 + x );

    int point;
    bool goal = false;

    int sc = map[ys][xs];

    /*
    for ( int i=0; i<=h; i++ ) {
      for ( int j=0; j<=w; j++ ) {
	cout << map[i+1][j+1];
      }
      cout << endl;
    }
    cout << endl;
    */
    int xn,yn;
    if ( map[yg][xg] == sc ) {
      if ( sc == 0 || map[yg][xg] == 0 ) {
      } else {
      while ( !next.empty() ) {
	point = next.front();
	next.pop();
	xn = point%1000;
	yn = point/1000;

	if (map[yn][xn] == 0 )
	  continue;

	if (point == yg*1000+xg) {
	  goal = true;
	  break;
	}

	for ( int i=0; i<4; i++ ) {
	  if ( check[yn+dy[i]][xn+dx[i]] ) {
	    check[yn+dy[i]][xn+dx[i]] = false;
	    if ( map[yn+dy[i]][xn+dx[i]] == sc ) {
	      next.push((yn+dy[i])*1000+ xn +dx[i]);
	    }
	  }
	}
      }
      }
    }

    if ( goal )
      cout << "OK\n";
    else
      cout << "NG\n";
  }
}