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----------------------------------------------------------------------------------------------------------------------
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<string>
#include<cctype>
#include<string>
#include<vector>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<bitset>
#include<map>
#include<algorithm>
#include<memory>


//using namespace--------------------------------------------------------------------------------------------------------------
using namespace std;

//define,const-----------------------------------------------------------------------------------------------------------------
#define rep(i, n) for(int i = 0; i < n; i++)
const int INF = 1 << 25;
#define MAX 1000

//global-----------------------------------------------------------------------------------------------------------------------
int board_range_w, board_range_h, start_x, start_y, goal_x, goal_y;
int color[MAX][MAX];
bool dp[MAX][MAX];

//function---------------------------------------------------------------------------------------------------------------------
bool solve(int x, int y, int before_x, int before_y){
	if ( x == goal_x && y == goal_y )
		return true;
	if ( !color[x][y] ){
		return dp[x][y] = false;
	}
	if ( x == 0 || y == 0 )
		return dp[x][y] = false;
	if ( color[x][y] == color[x + 1][y] && x + 1 != before_x && dp[x + 1][y] )
		if ( solve(x + 1, y, x, y) )
			return true;
	if ( color[x][y] == color[x][y + 1] && y + 1 != before_y && dp[x][y + 1] )
		if ( solve(x, y + 1, x, y) )
			return true;
	if ( color[x][y] == color[x][y - 1] && y - 1 != before_y && dp[x][y - 1] )
		if ( solve(x, y - 1, x, y) )
			return true;
	if ( color[x][y] == color[x - 1][y] && x - 1 != before_x && dp[x - 1][y] )
		if ( solve(x - 1, y, x, y) )
			return true;
	return dp[x][y] = false;
}



int main(){
	while ( scanf("%d %d", &board_range_w, &board_range_h) ) {
		if ( board_range_w == 0 && board_range_h == 0 )
			return 0;
		for ( int i = 0; i < 1000; i++ ){
			for ( int j = 0; j < 1000; j++ ){
				color[i][j] = 0;
				dp[i][j] = true;
			}
		}
		scanf("%d %d", &start_x, &start_y);
		scanf("%d %d", &goal_x, &goal_y);
		int block;
		scanf("%d", &block);
		for ( int i = 0; i < block; i++ ){
			//ブロック情報
			int block_color, block_quarter, block_start_x, block_start_y;
			scanf("%d %d %d %d", &block_color, &block_quarter, &block_start_x, &block_start_y);
			color[block_start_x + 1][block_start_y + 1] = block_color;
			color[block_start_x][block_start_y + 1] = block_color;
			color[block_start_x + 1][block_start_y] = block_color;
			color[block_start_x][block_start_y] = block_color;
			if ( block_quarter == 0 ){
				color[block_start_x + 2][block_start_y + 1] = block_color;
				color[block_start_x + 2][block_start_y] = block_color;
				color[block_start_x + 3][block_start_y + 1] = block_color;
				color[block_start_x + 3][block_start_y] = block_color;
			}										
			else{
				color[block_start_x + 1][block_start_y + 3] = block_color;
				color[block_start_x][block_start_y + 3] = block_color;
				color[block_start_x + 1][block_start_y + 2] = block_color;
				color[block_start_x][block_start_y + 2] = block_color;
			}
		}
		if ( solve(start_x, start_y, start_x, start_y) )
			printf("OK\n");
		else
			printf("NG\n");
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
using namespace std;
#define MAX 105
#define Nll -1
int w,h;
int xs,ys,xg,yg;
int blockNm;
int map[MAX][MAX];
typedef queue < pair<int,int> > Queue;
void setBlock(int color,int dir,int x,int y){
	int dx[]={2,0};
	int dy[]={0,2};
	int xb=x,yb=y;//x_base,y_base
	for(int i=0;i<2;i++,xb+=dx[dir],yb+=dy[dir]){
		map[yb][xb]
		        =map[yb][xb+1]
		        =map[yb+1][xb]
		        =map[yb+1][xb+1]=color;
	}
}
void init(){
	for(int i=0;i<MAX;i++)for(int j=0;j<MAX;j++)map[i][j]=-1;
}
void print(){
	for(int i=0;i<=h+1;i++){for(int j=0;j<=w+1;j++)printf("%2d",map[i][j]);cout<<endl;}
}
bool isGoal(int xs,int ys,int xg,int yg){
	int color=map[xs][ys];
	if(color==Nll)return false;
	int dx[]={ 0, 1, 0,-1};
	int dy[]={-1, 0, 1, 0};
	//cout<<"["<<w<<" "<<h<<"]"<<endl;
	Queue q;
	q.push(pair<int,int>(xs,ys));
	while(!q.empty()){
		pair<int,int> cur=q.front();q.pop();
	//	cout<<"cur("<<cur.first<<","<<cur.second<<")"<<endl;
		if(cur.first==xg&&cur.second==yg)return true;
		for(int i=0;i<4;i++){
//			cout<<"    next("<<cur.first+dx[i]<<","<<cur.second+dy[i]<<")"<<map[cur.first+dy[i]][cur.second+dx[i]]<<endl;
			if(cur.first+dx[i]<1||cur.first+dx[i]>w
					||cur.second+dy[i]<1||cur.second+dy[i]>h
					||map[cur.second+dy[i]][cur.first+dx[i]]!=color)continue;
			q.push(pair<int,int>(cur.first+dx[i],cur.second+dy[i]));
			map[cur.second+dy[i]][cur.first+dx[i]]=99;
		}
	}
	return false;
}
int main(){
	while(cin>>w>>h&&(w||h)){
		init();
		cin>>xs>>ys>>xg>>yg>>blockNm;
		for(int i=0;i<blockNm;i++){
			int color,dir,x,y;
			cin>>color>>dir>>x>>y;
			setBlock(color,dir,x,y);
		}
		//print();
		string ans=isGoal(xs,ys,xg,yg)?"OK":"NG";
		//cout<<"after"<<endl;
		//print();
		cout<<ans<<endl;
	}

	return 0;
}