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

int w, h, xs, ys, xg, yg, n;
int board[110][110];
bool used[110][110];

int dx1[8] = {0,1,2,3,0,1,2,3};
int dy1[8] = {0,0,0,0,1,1,1,1};

int dx2[8] = {0,0,0,0,1,1,1,1};
int dy2[8] = {0,1,2,3,0,1,2,3};

bool dfs(int x, int y, int xg, int yg, int color) {
    if (board[y][x] != color || used[y][x] || x <= 0 || y <= 0 || w < x || h < y) {
        return false;
    }
    if (x == xg && y == yg) {
        return true;
    }
    used[y][x] = true;
    bool ret = false;
    ret |= dfs(x+1, y, xg, yg, color);
    ret |= dfs(x-1, y, xg, yg, color);
    ret |= dfs(x, y+1, xg, yg, color);
    ret |= dfs(x, y-1, xg, yg, color);
    return ret;
}

int main() {
    while (cin >> w >> h, (w || h)) {
        memset(board, 0, sizeof board);
        cin >> xs >> ys >> xg >> yg >> n;
        int c, d, x, y;
        for (int i=0; i<n; ++i) {
            cin >> c >> d >> x >> y;
            if (d == 0) {
                for (int i=0; i<8; ++i) {
                    board[y + dy1[i]][x + dx1[i]] = c;
                }
            } else {
                for (int i=0; i<8; ++i) {
                    board[y + dy2[i]][x + dx2[i]] = c;
                }
            }
        }
        memset(used, false, sizeof used);
        if (board[ys][xs] && dfs(xs, ys, xg, yg, board[ys][xs])) {
            cout << "OK" << endl;
        } else {
            cout << "NG" << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>

#define rep(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define all(v) (v).begin(), (v).end()
#define rev(s) (s).rbegin(), (s).rend()
#define MP make_pair
#define X first
#define Y second

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef vector<int> vi;


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

int main(){
	int w, h;
	while(cin >> w >> h, w|h){
		w+=2, h+=2;
		vector<vi> v(h, vi(w, 0));
		int xs, ys, xg, yg;
		cin >> xs >> ys >> xg >> yg;
		int n;
		cin >> n;
		while(n--){
			int c, d, x, y;
			cin >> c >> d >> x >> y;
			int bw = d?2:4;
			int bh = d?4:2;
			rep(i, bh) rep(j, bw) v[y+i][x+j] = c;
		}

		queue<P> q;
		q.push(MP(xs, ys));
		int c = v[ys][xs];
		bool ok = false;
		if(c) while(!q.empty()){
			P p = q.front();
			q.pop();

			if(v[p.Y][p.X] != c) continue;
			v[p.Y][p.X] = 0;

			if(p == MP(xg, yg)){
				ok = true;
				break;
			}

			rep(i, 4){
				int x = p.X + dx[i];
				int y = p.Y + dy[i];
				q.push(MP(x, y));
			}
		}
		cout << (ok?"OK":"NG") << endl;
	}

	return 0;
}

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

int F[105][105];
int xg,yg;
int flag = 0;

void DFS(int Y,int X,int c){
  if(F[Y][X] != c){
    return;
  }
  if(Y == xg && X == yg){
    flag = 1;
  }

  F[Y][X] = 0;
  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,n;
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0)
      break;

    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 j=0;j<4;j++){
          F[x+j][y] = c;
          F[x+j][y+1] = c;
        }
      } else {
        for(int j=0;j<4;j++){
          F[x][y+j] = c;
          F[x+1][y+j] = c;
        }
      }
    }

  DFS(xs,ys,F[xs][ys]);
  if(flag == 1){
    cout << "OK" << endl;
  } else {
    cout << "NG" <<endl;
  }
  }
}

C++: #include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string toStr(T x) { ostringstream sout; sout << x; return sout.str();}
typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n) FOR(i,0,(n)-1)
const double EPS = 1e-12;
const double PI = acos(-1.0);
const int INF = INT_MAX/10;

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

struct state {
	int x, y;
	state(int x, int y) : x(x), y(y) {};
};

int main() {
	int w, h;
	while(cin >> w >> h, w) {
		vvi field(h, vi(w));
		vvi visit(h, vi(w));
		
		int xs, ys, xg, yg, n;
		cin >> xs >> ys >> xg >> yg >> n;

		int c, d, x, y;
		REP(i, n) {
			cin >> c >> d >> x >> y;
			REP(j, 4) {
				REP(k, 2) {
					if(d) {
						field[y+j][x+k] = c;
					} else {
						field[y+k][x+j] = c;
					}
				}
			}
		}

		queue<state> S;
		S.push(state(xs, ys));
		bool goal = false;
		while(!S.empty()) {
			state st = S.front();
			S.pop();

			if(st.x == xg && st.y == yg) {
				goal = true;
				break;
			}

			int nx, ny;
			REP(d, 4) {
				nx = st.x + dx[d];
				ny = st.y + dy[d];
				if(0<=nx && nx<w && 0<=ny && ny < h) {
					if(!visit[ny][nx] && field[ny][nx] == field[ys][xs]) {
						visit[ny][nx] = 1;
						S.push(state(nx, ny));
					}
				}

			}
		}

		if(goal) {
			cout << "OK" << endl;
		} else {
			cout << "NG" << endl;
		}
	}
}