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<iostream>
#include<algorithm>
#include<cstring>
#include<string>
#include<queue>
using namespace std;
int field[128][128];
bool memo[128][128];
int w,h;
void func(int x,int y,int c){
	if(x < 1 || y < 1 || x > w || y > h)return;
	if(memo[y][x])return ;
	if(field[y][x] != c)return ;
	memo[y][x] = 1;
	func(x-1,y,c);
	func(x+1,y,c);
	func(x,y+1,c);
	func(x,y-1,c);
	return ;
}
int main(){
	while(scanf("%d%d",&w,&h),w,h){
		int xs,ys,xg,yg,n;
		memset(field,0,sizeof(field));
		memset(memo,0,sizeof(memo));
		scanf("%d%d%d%d%d",&xs,&ys,&xg,&yg,&n);
		for(int i = 0; i < n; i++){
			int c,d,x,y;
			scanf("%d%d%d%d",&c,&d,&x,&y);
			if(d == 0){
				for(int j = x; j < x + 4; j++){
					field[y][j] = c;
					field[y+1][j] = c;
				}
			}
			else{
				for(int j = y; j < y + 4; j++){
					field[j][x] = c;
					field[j][x+1] = c;
				}
			}
		}
		func(xs,ys,field[ys][xs]);
		cout << (memo[yg][xg]?"OK":"NG") << endl;
	}
	return 0;
}

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) {
        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 <iostream>
#include <cstring>
using namespace std;

int a;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int board[105][105];

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

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

int xx[4] = {0, 1, 0, -1};
int yy[4] = {1, 0, -1, 0};
int block[100][100];
bool put[100][100];
int already[100][100];
int w, h;
int xs, ys;
int xg, yg;
bool dfs(int nex, int ney);

int main(){
  int n;
  
  while(1){
    memset(block, 0, sizeof(block));
    memset(already, 0, sizeof(already));
    memset(put, 0, sizeof(put));
    cin >> w >> h;
    if(w == 0 && h == 0) break;
    cin >> xs >> ys;
    xs--; ys--;
    cin >> xg >> yg;
    xg--; yg--;
    cin >> n;
    for(int i = 0; i < n; i++){
      int c, d, x, y;
      int wide, high;
      cin >> c >> d >> x >> y;
      x--; y--;
      if(d){
	wide = 2; high = 4;
      }
      else{
	wide = 4; high = 2;
      }
      for(int j = 0; j < high; j++){
	for(int k = 0; k < wide; k++){
	  block[y+j][x+k] = c;
	  put[y+j][x+k] = true;
	}
      }
    }
    bool ans = false;
    if(block[ys][xs] == block[yg][xg]){
      ans = dfs(xs, ys);
      if(ans) cout << "OK" << endl;
      else cout << "NG" << endl;
    }
    else cout << "NG" << endl;
  }
}

bool dfs(int nex, int ney){
  already[nex][ney] = 1;
  if(nex == xg && ney == yg) return true;
  for(int i = 0; i < 4; i++){
    int nx = nex + xx[i];
    int ny = ney + yy[i];
    if(0 <= nx && 0 <= ny && ny < h && nx < w && put[ny][nx] && !already[ny][nx] && block[ys][xs] == block[ny][nx]) return dfs(nx, ny);
  }
  return false;
}