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>
using namespace std;
 
int xg,yg,w,h,n;
char a[1000][1000],s;
 
bool dfs(int x,int y)
{
        if(x==xg&&y==yg)
                return true;
        a[y][x]='0';
        if(0<=x&&x<w&&0<=y-1&&y-1<h&&a[y-1][x]==s)
                if(dfs(x,y-1)) return true;
        if(0<=x&&x<w&&0<=y+1&&y+1<h&&a[y+1][x]==s)
                if(dfs(x,y+1)) return true;
        if(0<=x-1&&x-1<w&&0<=y&&y<h&&a[y][x-1]==s)
                if(dfs(x-1,y))  return true;
        if(0<=x+1&&x+1<w&&0<=y&&y<h&&a[y][x+1]==s)
                if(dfs(x+1,y)) return true;
        return false;
}
 
int main()
{
        int xs,ys,xb,yb,co,d,i,j;
        while(cin>>w>>h,w)
        {
                cin>>xs>>ys>>xg>>yg;
                for(i=0;i<h;i++)
                {
                        for(j=0;j<w;j++)
                        {
                                a[i][j]='0';
                        }
                }
                cin>>n;
                for(i=0;i<n;i++)
                {
                        cin>>co>>d>>xb>>yb;
                        if(d)
                        {
                                if(co==1)
                                {
                                        a[yb][xb]='1';
                                        a[yb][xb+1]='1';
                                        a[yb+1][xb]='1';
                                        a[yb+1][xb+1]='1';
                                        a[yb+2][xb]='1';
                                        a[yb+2][xb+1]='1';
                                        a[yb+3][xb]='1';
                                        a[yb+3][xb+1]='1';
                                }
                                else if(co==2)
                                {
                                        a[yb][xb]='2';
                                        a[yb][xb+1]='2';
                                        a[yb+1][xb]='2';
                                        a[yb+1][xb+1]='2';
                                        a[yb+2][xb]='2';
                                        a[yb+2][xb+1]='2';
                                        a[yb+3][xb]='2';
                                        a[yb+3][xb+1]='2';
                                }
                                else if(co==3)
                                {
                                        a[yb][xb]='3';
                                        a[yb][xb+1]='3';
                                        a[yb+1][xb]='3';
                                        a[yb+1][xb+1]='3';
                                        a[yb+2][xb]='3';
                                        a[yb+2][xb+1]='3';
                                        a[yb+3][xb]='3';
                                        a[yb+3][xb+1]='3';
                                }
                                else if(co==4)
                                {
                                        a[yb][xb]='4';
                                        a[yb][xb+1]='4';
                                        a[yb+1][xb]='4';
                                        a[yb+1][xb+1]='4';
                                        a[yb+2][xb]='4';
                                        a[yb+2][xb+1]='4';
                                        a[yb+3][xb]='4';
                                        a[yb+3][xb+1]='4';
                                }
                                else
                                {
                                        a[yb][xb]='5';
                                        a[yb][xb+1]='5';
                                        a[yb+1][xb]='5';
                                        a[yb+1][xb+1]='5';
                                        a[yb+2][xb]='5';
                                        a[yb+2][xb+1]='5';
                                        a[yb+3][xb]='5';
                                        a[yb+3][xb+1]='5';
                                }
                        }
                        else
                        {
                                if(co==1)
                                {
                                        a[yb][xb]='1';
                                        a[yb+1][xb]='1';
                                        a[yb][xb+1]='1';
                                        a[yb+1][xb+1]='1';
                                        a[yb][xb+2]='1';
                                        a[yb+1][xb+2]='1';
                                        a[yb][xb+3]='1';
                                        a[yb+1][xb+3]='1';
                                }
                                else if(co==2)
                                {
                                        a[yb][xb]='2';
                                        a[yb+1][xb]='2';
                                        a[yb][xb+1]='2';
                                        a[yb+1][xb+1]='2';
                                        a[yb][xb+2]='2';
                                        a[yb+1][xb+2]='2';
                                        a[yb][xb+3]='2';
                                        a[yb+1][xb+3]='2';
                                }
                                else if(co==3)
                                {
                                        a[yb][xb]='3';
                                        a[yb+1][xb]='3';
                                        a[yb][xb+1]='3';
                                        a[yb+1][xb+1]='3';
                                        a[yb][xb+2]='3';
                                        a[yb+1][xb+2]='3';
                                        a[yb][xb+3]='3';
                                        a[yb+1][xb+3]='3';
                                }
                                else if(co==4)
                                {
                                        a[yb][xb]='4';
                                        a[yb+1][xb]='4';
                                        a[yb][xb+1]='4';
                                        a[yb+1][xb+1]='4';
                                        a[yb][xb+2]='4';
                                        a[yb+1][xb+2]='4';
                                        a[yb][xb+3]='4';
                                        a[yb+1][xb+3]='4';
                                }
                                else
                                {
                                        a[yb][xb]='5';
                                        a[yb+1][xb]='5';
                                        a[yb][xb+1]='5';
                                        a[yb+1][xb+1]='5';
                                        a[yb][xb+2]='5';
                                        a[yb+1][xb+2]='5';
                                        a[yb][xb+3]='5';
                                        a[yb+1][xb+3]='5';
                                }
                        }
                }
                n=0;
                s=a[ys][xs];
                if(s!='0'){
                        if(dfs(xs,ys)){
                        	cout<<"OK"<<endl;
                        }
                        else {
                        	cout<<"NG"<<endl;
                        }
                 }
//                if(n)
//                        cout<<"OK"<<endl;
//                else
//                        cout<<"NG"<<endl;
        }
}