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 <queue>

using namespace std;

int w,h;
bool** flags;
char** map;

class Point{
public:
	int X,Y;
};

template <class T> T** NewArray(int w,int h){
	T** r = new T*[w];
	for(int i=0;i<w;i++){
		r[i] = new T[h];
		for(int j=0;j<h;j++){
			r[i][j] = 0;
		}
	}
	return r;
}

template <class T> void RemoveArray(T** array,int w,int h){
	for(int i=0;i<h;i++){
		delete[] array[i];
	}
	delete[] array;
}

bool Check(int x,int y,int c){
	if(x<0){return false;}
	if(y<0){return false;}
	if(x>=w){return false;}
	if(y>=h){return false;}
	if(flags[x][y]){return false;}
	if(map[x][y] != c){return false;}
	return true;
}

bool Solve(int sx,int sy,int gx,int gy){
	//printf("(%2d,%2d)->(%2d,%2d)\n",sx,sy,gx,gy);
	char c = map[sx][sy];
	queue<Point> pts;
	flags = NewArray<bool>(w + 1,h + 1);
	for(int i=0;i<w;i++){
		for(int j=0;j<h;j++){
			flags[i][j] = false;
		}
	}
	Point p,pp;
	p.X = sx;
	p.Y = sy;
	pts.push(p);
	flags[sx][sy] = true;
	
	bool res = false;
	
	while(pts.size() > 0){
		p = pts.front();
		pts.pop();
		if(flags[gx][gy] == true){
			res = true;
			break;
		}
		pp = p;
		pp.X -= 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.X += 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.Y -= 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
		pp = p;
		pp.Y += 1;
		if(Check(pp.X,pp.Y,c)){ pts.push(pp); flags[pp.X][pp.Y]=true; }
	}
	
	RemoveArray<bool>(flags,w + 1,h + 1);
	return res;
}

int main(){
	int xs,ys,xg,yg;
	
	while(scanf("%d %d",&w,&h) && w && h){
		w+=1;
		h+=1;
		map = NewArray<char>(w + 1,h + 1);
		scanf("%d %d %d %d",&xs,&ys,&xg,&yg);
		xs -= 1;
		ys -= 1;
		xg -= 1;
		yg -= 1;
		int n;
		scanf("%d",&n);
		int c,d,x,y;
		int xx,yy;
		for(int j=0;j<h;j++){
			for(int i=0;i<w;i++){
				//printf("%d ",map[i][j]);
				map[i][j] = 0;
			}
			//printf("\n");
		}
		
		for(int i=0;i<n;i++){
			scanf("%d %d %d %d",&c,&d,&x,&y);
			if(d == 0){
				xx = 4;
				yy = 2;
			}else{
				xx = 2;
				yy = 4;
			}
			x-=1;
			y-=1;
			for(int j=0;j<xx;j++){
				for(int k=0;k<yy;k++){
					//printf("(%2d+%2d,%2d+%2d) = %d\n",k,j,y,k,c);
					map[x+j][y+k] = c;
				}
			}
		}
		for(int j=0;j<h;j++){
			for(int i=0;i<w;i++){
				//printf("%d ",map[i][j]);
			}
			//printf("\n");
		}
		
		
		if(Solve(xs,ys,xg,yg)){
			printf("OK\n");
		}else{
			printf("NG\n");
		}
		RemoveArray<char>(map,w + 1,h + 1);
	}
}

C++: #include<iostream>

int field[102][102];//y,x
bool flag;
int n,a,sx,sy,gx,gy,col;

void erase(){
	for(int i=0; i<102; i++)
		for(int j=0; j<102; j++)
			field[i][j] = 0;
}

void DFS(int x, int y){
	int xx = x;
	int yy = y;

	if(xx == gx && yy == gy){
		flag = true;
		return;
	}

	xx++;
	if(field[yy][xx] == col)
		DFS(xx, yy);
	if(flag)
		return;

	xx--;
	yy++;
	if(field[yy][xx] == col)
		DFS(xx, yy);
	if(flag)
		return;
		
	xx--;
	yy--;
	if(field[yy][xx] == col)
		DFS(xx, yy);
	if(flag)
		return;
			
	xx++;
	yy--;
	if(field[yy][xx] == col)
		DFS(xx, yy);
}

int main(){
	int c,d,bx,by;
	using std::cin;
	while(true){
		flag = false;
		erase();
		cin >> n >> a;
		if(!n && !a)
			return 0;
		cin >> sx >> sy;
		cin >> gx >> gy;
		cin >> n;
		for(int i=0; i<n; i++){
			cin >> c >> d >> bx >> by;
			if(d==0){
				for(int h=by; h<by+2; h++)
					for(int k=bx; k<bx+4; k++)
						field[h][k] = c;
			}
			else{
				for(int h=by; h<by+4; h++)
					for(int k=bx; k<bx+2; k++)
						field[h][k] = c;
			}
		}
		col = field[gy][gx];
		DFS(sx, sy);
		if(flag)
			std::cout << "OK\n";
		else
			std::cout << "NG\n";
	}
}

C++: #include<iostream>

bool flag;
int n,sx,sy,gx,gy,col;

void erase(int** field){
	for(int i=0; i<102; i++)
		for(int j=0; j<102; j++)
			field[i][j] = 0;
}

void DFS(int x, int y, int** field){
	int xx = x+1;
	int yy = y;

	if(xx == gx && yy == gy){
		flag = true;
		return;
	}

	if(field[yy][xx] == col)
		DFS(xx, yy, field);
	if(flag)
		return;

	xx = x;
	yy = y+1;
	if(field[yy][xx] == col)
		DFS(xx, yy, field);
	if(flag)
		return;

	xx = x-1;
	yy = y;
	if(field[yy][xx] == col)
		DFS(xx, yy, field);
	if(flag)
		return;
			
	xx = x;
	yy = y-1;
	if(field[yy][xx] == col)
		DFS(xx, yy, field);
}

int main(){
	int field[102][102];//y,x
	int c,d,bx,by;
	using std::cin;
	while(true){
		flag = false;
		erase(field);
		cin >> c >> d;
		if(!c && !d)
			return 0;
		cin >> sx >> sy;
		cin >> gx >> gy;
		cin >> n;
		for(int i=0; i<n; i++){
			cin >> c >> d >> bx >> by;
			if(d==0){
				for(int h=by; h<by+2; h++)
					for(int k=bx; k<bx+4; k++)
						field[h][k] = c;
			}
			else{
				for(int h=by; h<by+4; h++)
					for(int k=bx; k<bx+2; k++)
						field[h][k] = c;
			}
		}
		col = field[gy][gx];
		DFS(sx, sy, field);
		if(flag)
			std::cout << "OK\n";
		else
			std::cout << "NG\n";
	}
}

C++: #include <iostream>
using namespace std;

int F[102][102];
int xg,yg;

void Maze(int X,int Y,int C){
	if(F[X][Y]!=C)
		return;

	if(X==xg&&Y==yg)
		cout << "OK"<<endl;
		return;


	F[X][Y]='.';

	Maze(X-1,Y  ,C);
	Maze(X  ,Y+1,C);
	Maze(X+1,Y  ,C);
	Maze(X  ,Y-1,C);

	cout <<"NG"<<endl;
	
}



int main(){	
	while(1){
		int w,h,xs,ys,n,c,d,x,y;

		cin >>w>>h;
		cin >>xs>>ys;
		cin >>xg>>yg;
		cin >>n;


		if(w==0&&h==0)
			return 0;

		int N=0;
		while(N<n){
			cin >>c>>d>>x>>y;
			if(d==1){
				for(int i=x; i<x+2; i++)
					for(int j=y; j<y+4; j++)
						F[i][j]=c;
			}else{
				for(int i=x; i<x+4; i++)
					for(int j=y; j<y+2; j++)
						F[i][j]=c;
			}
			N++;
		}
			//for(int i=1; i<=h; i++){
					//for(int j=1; j<=w; j++){
						//cout <<F[j][i];
					//}
				//cout << endl;
			//}
		

		Maze(xs,ys,F[xs][ys]);

	}

}