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>
#define int long long
using namespace std;
int w,h,xs,ys,xg,yg,n,c,d,x,y,nok,sc;
int fld[101][101];
int dx[]={0,1,0,-1},dy[]={1,0,-1,0};
void dfs(int fx,int fy){
    if(fld[fy][fx]!=sc||fx<0||fx>w-1||fy<0||fy>h-1)return;
    if(fx==xg-1&&fy==yg-1){
        if(sc==fld[fy][fx])nok=1;
    }
    fld[fy][fx]=0;
    for(int i=0;i<4;i++){
        dfs(fx+dx[i],fy+dy[i]);
    }
}
signed main(){
    for(;;){
        cin>>w>>h;
        if(w==0&&h==0)break;
        cin>>xs>>ys;
        cin>>xg>>yg;
        cin>>n;
        nok=0;
        fill(fld[0],fld[0]+101*101,0);
        for(int i=0;i<n;i++){
            cin>>c>>d>>x>>y;
            x--,y--;
            if(d==0){
                for(int j=0;j<2;j++){
                    for(int k=0;k<4;k++){
                        fld[y+j][x+k]=c;
                    }
                }
            }
            if(d==1){
                for(int j=0;j<4;j++){
                    for(int k=0;k<2;k++){
                        fld[y+j][x+k]=c;
                    }
                }
            }
        }
        sc=fld[ys-1][xs-1];
        for(int j=0;j<h;j++){
            for(int k=0;k<w;k++){
                cout<<fld[j][k];
            }
            cout<<endl;
        }
        if(fld[0][0]!=0){
            dfs(0,0);
        }
        if(nok==1)cout<<"OK"<<endl;
        else cout<<"NG"<<endl;
    }
    return 0;
}

C++: #include<stdio.h>
#include<queue>
#include<algorithm>
using namespace std;
int f[200][200];
int v[200][200];
int dx[]={0,-1,0,1};
int dy[]={1,0,-1,0};
int main(){
	int a,b;
	while(scanf("%d%d",&a,&b),a){
		int xs,ys,xg,yg;
		scanf("%d%d%d%d",&xs,&ys,&xg,&yg);
		xs--;ys--;xg--;yg--;
		int n;
		scanf("%d",&n);
		for(int i=0;i<200;i++)
			for(int j=0;j<200;j++)
				f[i][j]=v[i][j]=0;
		for(int i=0;i<n;i++){
			int p,q,r,s;scanf("%d%d%d%d",&p,&q,&r,&s);
			r--;s--;
			if(q==0){
				for(int j=0;j<4;j++)
					for(int k=0;k<2;k++)
						f[r+j][s+k]=p;
			}else{
				for(int j=0;j<2;j++)
					for(int k=0;k<4;k++)
						f[r+j][s+k]=p;
			}
		}
		if(f[xs][ys]!=f[xg][yg]||!f[xs][ys]){
			printf("NG\n");
			continue;
		}
		queue<pair<int,int> >Q;
		v[xs][ys]=1;
		Q.push(make_pair(xs,ys));
		while(Q.size()){
			int row=Q.front().first;
			int col=Q.front().second;
			Q.pop();
			for(int i=0;i<4;i++){
				if(0<=row+dx[i]&&row+dx[i]<a&&0<=col+dy[i]&&col+dy[i]<b&&!v[row+dx[i]][col+dy[i]]&&f[row+dx[i]][col+dy[i]]==f[row][col]){
					v[row+dx[i]][col+dy[i]]=1;
					Q.push(make_pair(row+dx[i],col+dy[i]));
				}
			}
		}
		if(v[xg][yg])printf("OK\n");
		else printf("NG\n");
	}
}

C++: #include <stdio.h>
#include <queue>
#include <iostream>

#define MAX 110

int map[MAX][MAX];

void makemap(int c, int d, int x, int y);

int bfs(int xs,int ys,int xg,int yg);

int main()
{
	int w,h,xs,ys,xg,yg,n,c,d,x,y;
	while(1)
	{
	scanf("%d%d",&w,&h);
	if(w==0 && h==0)
		return 0;
	scanf("%d%d",&xs,&ys);
	scanf("%d%d",&xg,&yg);
	scanf("%d",&n);

	for(int i=0;i<MAX;i++)
		for(int j=0;j<MAX;j++)
			map[i][j]=0;

	for(int i=0;i<n;i++)
	{
		scanf("%d%d%d%d",&c,&d,&x,&y);
		makemap(c,d,x,y);
	}
	if(map[xs+1][ys+1]==0)
		printf("NG\n");
	if(bfs(xs+1,ys+1,xg+1,yg+1)==0)
		printf("OK\n");
	else
		printf("NG\n");
	}
	return 0;
}

void makemap(int c, int d, int x, int y)
{
	if(d==0)
		for(int i=x+1;i<x+5;i++)
			for(int j=y+1;j<y+3;j++)
				map[i][j]=c;
	else
		for(int i=x+1;i<x+3;i++)
			for(int j=y+1;j<y+5;j++)
				map[i][j]=c;
}

int bfs(int xs,int ys,int xg,int yg)
{
	int startcolor=map[xs][ys];
	int nowx=xs,nowy=ys;
	using namespace std;
	queue<int> x;
	queue<int> y;
	while(1)
	{
		if(nowx==xg && nowy == yg && map[nowx][nowy]==startcolor )
			return 0;
		map[nowx][nowy]=0;
		if(map[nowx-1][nowy]==startcolor)
		{
			x.push(nowx-1);
			y.push(nowy);
		}
		if(map[nowx][nowy-1]==startcolor)
		{
			x.push(nowx);
			y.push(nowy-1);
		}
		if(map[nowx][nowy+1]==startcolor)
		{
			x.push(nowx);
			y.push(nowy+1);
		}
		if(map[nowx+1][nowy]==startcolor)
		{
			x.push(nowx+1);
			y.push(nowy);
		}
		if(x.empty()==1 && y.empty()==1)
			return 1;
		nowx=x.front();
		nowy=y.front();
		x.pop();
		y.pop();
	}
}

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;

bool isMaze;
int blocks[105][105], xg, yg, w,h;

void dfs(int target, int x, int y){
    if(x < 0 || y < 0 || x >= w || y >= h) return;
    if(x == xg && y == yg){
        isMaze = true;
        return;
    }
    if(blocks[y][x] != target || blocks[y][x] == 0){
        return;
    }

    blocks[y][x] = 9;
    
    dfs(target, x + 1, y);
    dfs(target, x - 1, y);
    dfs(target, x, y + 1);
    dfs(target, x, y - 1);
    return;
}

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

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