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;

char F[102][102];
void DFC(int y,int x);
void block_set(int c,int d,int x,int y);
int cs;
int xg,yg;
bool result = false;

int main(){
  int H,W;
  while(1){
    result = false;
    cin >> H >> W;
    if(H==0&&W==0)
      break;
    int xs,ys;
    cin >> xs >> ys >> xg >> yg;
    int n;
    cin >> n;
    int c,d,x,y;
    for(int i=0;i<n;i++){
      cin >> c >> d >> x >> y;
      if(i==0)
        cs = c;
        block_set(c,d,x,y);
    }

    DFC(xs,ys);

    if(result)
      cout << "YES" << endl;
      else
      cout << "NO" << endl;
  }

  return 0;
}

void DFC(int x,int y){
  if(F[x][y]!=cs)
    return;

  if(x==xg,y==yg)
    result = true;

  F[x][y]=0;

  DFC(x-1,y);
  DFC(x+1,y);
  DFC(x,y-1);
  DFC(x,y+1);
}

void block_set(int c,int d,int x,int y){
  for(int i=0;i<2;i++){
    for(int j=0;j<4;j++){
      if(d){
        F[x+i][y+j] = c;
      }
      else{
        F[x+j][y+i] = c;
      }
    }
  }
}

C++: #include <iostream>
#include <queue>

using namespace std;

bool bfs(pair<int,int>[],int **);

int main(void){
	int w,h,xs,ys,xg,yg,n,**board,dr[2][2]={4,2,2,4};
	pair<int,int> sg[2];

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

		sg[0] = make_pair(xs,ys);
		sg[1] = make_pair(xg,yg);

		board = new int*[w+2];
		for(int i=0;i<w+2;i++)
			board[i] = new int[h+2];

		for(int i=0;i<h+2;i++)
			for(int j=0;j<w+2;j++)
				board[j][i]=0;

		for(int i=0;i<n;i++){
			int c,d,x,y;
			cin >> c >> d >> x >> y;
			for(int j=0;j<dr[d][0];j++)
				for(int k=0;k<dr[d][1];k++)
					board[x+j][y+k]=c;
		}

		cout << (bfs(sg,board)?"OK":"NG");
		cout << endl;

		for(int i=0;i<w+2;i++)
			delete [] board[i];
		delete [] board;	
	}while(w!=0||h!=0);

	return 0;
}

bool bfs(pair<int,int> sg[],int **board){
	queue< pair<int,int> > Q;
	pair<int,int> cur;
	int dx[4]={-1,0,1,0},dy[4]={0,1,0,-1},c;

	Q.push(sg[0]);
	cur=Q.front();
	c=board[cur.first][cur.second];

	while(!Q.empty()&&c!=0){
		cur=Q.front();
		Q.pop();
		board[cur.first][cur.second]=0;

		if(cur==sg[1])
			return true;

		for(int i=0;i<4;i++)
			for(int j=0;j<4;j++)
				if(board[cur.first+dx[i]][cur.second+dy[j]]==c)
					Q.push(make_pair(cur.first+dx[i],cur.second+dy[j]));

	}
	return false;
}

C++: #include <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) begin(r),end(r)
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)
#define vvl(v,w,h,init) vector<vector<ll>> v(w,vector<ll>(h,init))
#define mp(a,b) make_pair(a,b)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using pii = pair<int,int> ;
using pll = pair<ll,ll> ;

const int mod = 1000000007;
constexpr ll inf = ((1<<30)-1)*2+1 ;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0,1,-1,1,-1};
const int dx[] = {0,-1,0,1,1,-1,-1,1};

inline bool value(int x,int y,int w,int h){
  return (x >= 0 && x < w && y >= 0 && y < h);
}
int xs,ys,xg,yg,n;
ll w,h;
vector<vector<ll>> field;
vector<vector<ll>> f;

bool dfs(int x,int y,int c){
  if(f[x][y] != inf) return false;
  if(x == xg && y == yg) return true;
  f[x][y] = 1;
  bool res = false;
  rep(i,4){
    int nx = x + dx[i],ny = y + dy[i];
    if(value(nx,ny,w,h) && field[nx][ny] == c){
      res |= dfs(nx,ny,c);
    }
  }
  return res;
}

void solve(){
  rep(i,5){
    f = vector<vector<ll>>(w+1,vector<ll>(h+1,inf));

    if(dfs(xs,ys,i)){
      cout << "OK" << endl;
      return ;
    }
  }
  cout << "NG" << endl;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  while(cin >> w >> h && w+h){
    field = vector<vector<ll>>(w+1,vector<ll>(h+1,0));
    cin >> xs >> ys >> xg >> yg >> n;
    xs--,ys--,xg--,yg--;
    int c,d,x,y;
    rep(i,n){
      cin >> c >> d >> x >> y;
      --x,--y,--c;
      rep(j,2){
        rep(k,4){
          ll dx = k,dy = j;
          if(d){
            swap(dx,dy);
          }
          field[x+dx][y+dy] = c;
        }
      }
    }
    solve();
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

int flag=0;
int mp[102][102];
int sn[102][102];
int bc;

int px[4]={0,1,0,-1};
int py[4]={1,0,-1,0};

int slv(int xs,int ys);

int w,h,xg,yg;
int n,c,d,x,y;  

int main(){
  int xs,ys;
  while(1){
    cin>>w>>h;
    if(w==0 && h==0)return(0);
    cin>>xs>>ys;
    cin>>xg>>yg;
    flag=0;
    cin>>n;
    memset(mp,0,sizeof(mp));
    memset(sn,0,sizeof(sn));
    for(int i=0;i<n;i++){
      cin>>c>>d>>x>>y;
      if(d==1){
	for(int j=0;j<4;j++){
	  for(int k=0;k<2;k++)mp[x+k][y+j]=c;
	}
      }
      else{
	for(int j=0;j<2;j++){
	  for(int k=0;k<4;k++)mp[x+k][y+j]=c;
	}
      }
    }
    
    bc=mp[xs][ys];
    
    slv(xs,ys);
    
    if(flag)cout<<"OK"<<endl;
    else cout<<"NG"<<endl;
    
  }
}

int slv(int xs,int ys){
  if(xs==xg && ys==yg){
    flag=1;
    return(0);
  }
  
  for(int i=0;i<4;i++){
    xs+=px[i];
    ys+=py[i];
    if(bc==mp[xs][ys] && sn[xs][ys]==0){
      sn[xs][ys]=1;
      slv(xs,ys);
    }
    xs-=px[i];
    ys-=py[i];
  }
  return(0);
}