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<queue>
#define dr direction
#define cl color
#define fi first
#define se second

using namespace std;
typedef pair<int, int> pii;

class Block{
public:
    int color;// 1~5
    int direction;// 0:-, 1:|
    int x, y;
    void init(int c, int d, int xx, int yy);
};

void Block::init(int c, int d, int xx, int yy){
    color=c;
    direction=d;
    x=xx;
    y=yy;
}

int w, h, xs, ys, xg, yg, n;
int fld[100][100], dis[100][100];
const pii dxdy[]={{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
const int inf=1e8;

string solve(){// bfs
    queue<pii> qu;
    qu.push(make_pair(ys, xs));
    int C=fld[ys][xs];
    fill(dis[0], dis[100], inf);
    dis[ys][xs]=0;

    if(C==0) return "NO";
    while(!qu.empty()){
        pii now=qu.front(); qu.pop();
        if(now.fi==yg&&now.se==xg){
            return "OK";
        }

        for(int k=0; k<4; k++){
            pii nx=make_pair(now.fi+dxdy[k].fi, now.se+dxdy[k].se);
            if(!(0<=nx.fi&&nx.fi<h&&0<=nx.se&&nx.se<w)) continue;
            if(fld[nx.fi][nx.se]!=C) continue;
            if(dis[nx.fi][nx.se]!=inf) continue;

            dis[nx.fi][nx.se]=dis[now.fi][now.se]+1;
            qu.push(nx);
        }
    }

    return "NO";
}

int main(){

    while(1){
        cin>> w>> h;
        if(w==0&&h==0) break;
        cin>> xs>> ys>> xg>> yg>> n;
        xs--; ys--; xg--; yg--;
        Block block[n];
        for(int i=0; i<n; i++){
            int c, d, xx, yy;
            cin>> c>> d>> xx>> yy;
            xx--; yy--;
            block[i].init(c, d, xx, yy);
        }

        // make field
        for(int k=0; k<n; k++){
            int X=block[k].x, Y=block[k].y;
            if(block[k].dr==0){
                for(int i=0; i<2; i++){
                    for(int j=0; j<4; j++){
                        fld[Y+i][X+j]=block[k].cl;
                    }
                }
            }else{
                for(int i=0; i<4; i++){
                    for(int j=0; j<2; j++){
                        fld[Y+i][X+j]=block[k].cl;
                    }
                }
            }
        }
/*
        for(int i=0; i<w; i++){
            for(int j=0; j<h; j++){
                cout<< fld[i][j]<<" ";
            }
            cout<< endl;
        }
//*/
        cout<< solve()<< endl;
    }

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
int needleX[4] = { -1,0,1,0 };
int needleY[4] = { 0,1,0,-1 };
bool dfs(int x, int y, int goalx, int goaly, std::vector<std::vector<bool>>&canGo) {
    if (x == goalx && y == goaly) { return true; }

    canGo[x][y] = false;
    for (int i = 0; i < 4; i++) {
        int next_x = x + needleX[i];
        int next_y = y + needleY[i];

        if (canGo[next_x][next_y]) {
            bool flag = dfs(next_x, next_y, goalx, goaly, canGo);
            if (flag)
                return true;
        }
    }
    return false;
}
int main(void) {
    int h, w, n;
    std::cin >> h >> w;
    std::vector<std::string> ans;
    while(h!=0&& w!=0){
        int color, orient, leftX, leftY;
        int sx, sy, gx, gy;
        std::cin >> sx >> sy >> gx >> gy;
        std::vector<std::vector<int>> board(h + 2, std::vector<int>(w + 2, 0));
        std::vector<std::vector<bool>> canGo(h + 2, std::vector<bool>(w + 2, false));
        std::cin >> n;
        int start = 0, goal = 0;
        for (int i = 0; i < n; i++) {
            std::cin >> color >> orient >> leftX >> leftY;


            if (orient == 0) {
                for (int j = 0; j <= 3; j++) {
                    for (int k = 0; k <= 1; k++) {
                        board[leftX + j][leftY + k] = color;
                        if (leftX + j == sx && leftY + k == sy) {
                            start = color;
                        }
                        else if (leftX + j == gx && leftY + k == gy) {
                            goal = color;
                        }
                    }
                }

            }
            else {
                for (int j = 0; j <= 1; j++) {
                    for (int k = 0; k <= 3; k++) {
                        board[leftX + j][leftY + k] = color;
                        if (leftX + j == sx && leftY + k == sy) {
                            start = color;
                        }
                        else if (leftX + j == gx && leftY + k == gy) {
                            goal = color;
                        }
                    }
                }
            }
        }
        if (start != goal) {
            ans.push_back("NG");
            
            break;
        }
        for (int i = 0; i <= h; i++) {
            for (int j = 0; j <= w; j++) {
                if (board[i][j] == start) {
                    canGo[i][j] = true;
                }
            }
        }
        bool result = dfs(sx, sy, gx, gy, canGo);
        if (result) { ans.push_back("OK"); }
        else { ans.push_back("NG"); }
        std::cin >> h >> w;
    }
    for (int i = 0; i < ans.size(); i++) {
        std::cout << ans[i] << std::endl;
    }
    return 0;
}