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<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define it ::iterator
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double ESP=1e-10;
using namespace std;
int x[4]={-1,1,0,0};
int y[4]={0,0,-1,1};
int color;
void func(vector<vector<int> >&in,vector<vector<int> >&map,int a,int b){
  //cout<<a<<" "<<b<<endl;
  map[a][b]=2;
  rep(i,4)if(in[a+x[i]][b+y[i]]==color&&map[a+x[i]][b+y[i]]==1)func(in,map,a+x[i],b+y[i]);
}
int main(){
  int n,m;
  while(cin>>m>>n,n||m){
    vector<vector<int> >in(n+2,vector<int>(m+2));
    int xs,ys,xg,yg;
    cin>>ys>>xs>>yg>>xg;
    int q;
    cin>>q;
    rep(i,q){
      int a,b,c,d;
      cin>>a>>b>>c>>d;
      if(b)rep(i,2)rep(j,4)in[i+c][j+d]=a;
      else rep(i,4)rep(j,2)in[i+c][j+d]=a;
    }
    //cout<<n<<" "<<m<<endl;
    //loop(i,1,n+1){loop(j,1,m+1)cout<<" "<<in[i][j];cout<<endl;}

    if(in[xs][ys]==0||in[xg][yg]==0){cout<<"NG"<<endl;continue;}
    color=in[xs][ys];
    vector<vector<int> >map(n+2,vector<int>(m+2));
    loop(i,1,n+1)loop(j,1,m+1)map[i][j]=1;
    //loop(i,1,n+1){loop(j,1,m+1)cout<<" "<<map[i][j];cout<<endl;}

    func(in,map,xs,ys);
    if(map[xg][yg]==2)cout<<"OK"<<endl;
    else cout<<"NG"<<endl;
    //cout<<n<<" "<<m<<endl;
    //loop(i,1,n+1){loop(j,1,m+1)cout<<" "<<map[i][j];cout<<endl;}
  }
}

C++: #include <iostream>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;

int w,h,sx,sy,gx,gy,d[100][100],dx[4]={1,0,-1,0},dy[4]={0,1,0,-1},C;
int field[101][101];
const int INF=9999999;
typedef pair<int,int> P;

void bfs(){
	queue<P> que;
	for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)d[i][j]=INF;
	que.push(P(sy,sx));
	d[sy][sx]=0;
	while(!que.empty()){
		P p=que.front(); que.pop();
		if(p.first==gy&&p.second==gx)break;
		for(int i=0;i<4;i++){
			int ny=p.first+dx[i],nx=p.second+dy[i];
			if(1<=ny&&ny<=h&&1<=nx&&nx<=w&&field[ny][nx]==C&&d[ny][nx]==INF){
			que.push(P(ny,nx));
			d[ny][nx]=d[p.first][p.second]+1;
			}
		}
	}
	if(d[gy][gx]==INF)cout<<"NG"<<endl;
	else cout<<"OK"<<endl;
}

int main() {
	while(cin>>h>>w){
		if(!h)return 0;
		int n,c,di,x,y;
		cin>>sx>>sy>>gx>>gy>>n;
		for(int i=1;i<=h;i++)for(int j=1;j<=w;j++)field[i][j]=0;
		for(int i=0;i<n;i++){
			cin>>c>>di>>x>>y;
			for(int j=y;j<=y+2+di*2;j++)for(int k=x;k<=x+2+!di*2;k++)field[j][k]=c;
		}
		C=field[1][1];
		bfs();
	}
}

C++: #include <iostream>
#include <cstring>
using namespace std;
int dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
int w,h,xg,yg,xs,ys,n,fld[101][101];
bool dfs(int x,int y,int c){
	if(c==0||fld[x][y]!=c)return false;
	if(x==xg&&y==yg)return true;
	fld[x][y]=0;
	for(int i=0;i<4;i++)if(dfs(x+dx[i],y+dy[i],c))return true;
	return false;
}
int main(){
	while(cin>>w>>h,w,h){
		cin>>xs>>ys>>xg>>yg>>n;
		for(int i=0;i<n;i++){
			int x,y,cc,d,r,l;
			cin>>cc>>d>>x>>y;
			if(d){r=4;l=2;}else{r=2;l=4;}
			for(int j=x;j<x+l;j++)for(int k=y;k<y+r;k++)fld[j][k]=cc;
		}
		if(dfs(xs,ys,fld[xs][ys]))cout<<"OK"<<endl;
		else cout<<"NG"<<endl;
	}
}