#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

typedef unsigned int uint;
typedef unsigned long long uint64;
typedef long long sint64;

int x[10], y[10];

int main(int argc, char* argv[])
{
    uint q;
    cin >> q;

    for (; q; --q) {
        uint n;
        cin >> n;

        int xm = 10000,
            xx = -10000,
            ym = 10000,
            yx = -10000;

        for (uint i = 0; i < n; ++i) {
            cin >> x[i] >> y[i];

            if (x[i] < xm)
                xm = x[i];
            if (x[i] > xx)
                xx = x[i];

            if (y[i] < ym)
                ym = y[i];
            if (y[i] > yx)
                yx = y[i];
        }

        bool f = true;
        for (uint i = 0; i < n; ++i) {
            if (x[i] != xm && x[i] != xx && y[i] != ym && y[i] != yx) {
                f = false;
                break;
            }
        }

        cout << (f ? "YES\n" : "NO\n");
    }

    return 0;
}