#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <climits>
#include <algorithm>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <cassert>
#include <vector>
#define all(x) x.begin() , x.end()
#define fi first
#define se second
#define pb push_back
#define umax( x , y ) x = max( x , (y) )
#define umin( x , y ) x = min( x , (y) )
#define For( i , a ) for(int i=1;i<=a;i++)
#define ort (b+s)/2
#define y2 asrwjaelkf
#define y1 asseopirwjaelkf
#define set multiset

using namespace std;

inline int read() {
    int res = 0 ;int neg ;
    while(true){char ch = getchar();if(ch>='0' && ch<='9' || ch=='-'){if(ch=='-') neg = -1;else neg = 1 , res = ch-'0';break;} }
    while(true){char ch = getchar();if(ch>='0' && ch<='9') res*=10 , res+=ch-'0';else break;}
    return res*neg;
}


typedef long long Lint;
typedef double db;
typedef pair<int,int> ii;
typedef pair<db,db> dd;
typedef pair<ii,int> iii;
typedef pair<ii,ii> i4;

const int maxn = 400320;
const int maxm = 1000020;
const int MOd = 1e9 + 7;

int a;
ii ar[maxn];

void solve() {

    scanf("%d",&a);
    for(int i=1;i<=a;i++) scanf("%d %d",&ar[i].fi,&ar[i].se);
    for(int i1=1;i1<=a;i1++)
        for(int i2=1;i2<=a;i2++)
            for(int i3=1;i3<=a;i3++)
                for(int i4=1;i4<=a;i4++) {
                    int c = 0;
                    for(int i=1;i<=a;i++) {
                        if( ar[i].fi == ar[i1].fi && abs( ar[i].se - ar[i3].se ) + abs( ar[i].se - ar[i4].se ) == abs( ar[i3].se - ar[i4].se ) ) continue;
                        if( ar[i].fi == ar[i2].fi && abs( ar[i].se - ar[i3].se ) + abs( ar[i].se - ar[i4].se ) == abs( ar[i3].se - ar[i4].se ) ) continue;
                        if( ar[i].se == ar[i3].se && abs( ar[i].fi - ar[i1].fi ) + abs( ar[i].fi - ar[i2].fi ) == abs( ar[i1].fi - ar[i2].fi ) ) continue;
                        if( ar[i].se == ar[i4].se && abs( ar[i].fi - ar[i1].fi ) + abs( ar[i].fi - ar[i2].fi ) == abs( ar[i1].fi - ar[i2].fi ) ) continue;
                        c = 1;
                        break;
                    }
                    if( !c ) {
                        printf("YES\n");
                        return;
                    }
                }
    printf("NO\n");
}

int main() {


    //freopen("asd.in","r",stdin);
    //freopen("out.txt","w",stdout);

    int n;
    scanf("%d",&n);
    while( n-- ) solve();

    return 0;
}