#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <fstream>
#include <iostream>
#include <list>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <valarray>
#include <vector>

#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#define repeat(i,n)     for(int i=0; i<(n); ++i)
#define repeat1(i,n)    for(int i=1; i<=(n); ++i)
#define range(i,l,r)    for(int i=(l); i<(r); ++i)

using namespace std;
typedef long long llint;

typedef pair<int, int> pii;

int iin();
llint   lin();
double  fin();

void input(vector<pii> &vp) {
    int x, y, n = vp.size();
    repeat(i, n) {
        x = iin();
        y = iin();
        vp[i] = pii(x, y);
    }
}

int cross(pii &a, pii &b, pii &c) {
    return ((a.first - c.first) * (b.second - c.second)
            - (a.second - c.second) * (b.first - c.first));
}

bool if_edge(vector<pii> &vp, vector<int> &e) {
    int n = vp.size(), a = e[0], b = e[1], c, sign;
    bool    flag = false, ans = true;
    repeat(i, n) {
        if(a == i || b == i)    continue;
        if((c=cross(vp[a], vp[b], vp[i])) == 0) {
            e.push_back(i);
            continue;
        }
        if(!flag) {
            flag = true;
            sign = c;
        }
        else if(c * sign < 0)   ans = false;
    }

    return ans;
}

bool solve() {
    int n = iin();
    vector<pii> points(n);
    int x1, x2, y1, y2;

    input(points);

    sort(points.begin(), points.end());

    x1 = points[0].first;
    x2 = x1;
    y1 = points[0].second;
    y2 = y1;

    range(i, 1, n) {
        if(points[i].first < x1)    x1 = points[i].first;
        else if(points[i].first > x2)    x2 = points[i].first;
        if(points[i].second < y1)   y1 = points[i].second;
        else if(points[i].second > y2)   y2 = points[i].second;
    }

    repeat(i, n) {
        if(points[i].first != x1 && points[i].first != x2 &&
            points[i].second != y1 && points[i].second != y2)
            return false;
    }

    return true;
}

int main() {
    int q = iin();

    repeat(i, q) {
        if(solve()) printf("YES\n");
        else    printf("NO\n");
    }
    return 0;
}

//////////////////////////////////////////////////////////////////////////////

int iin() {
    int x;
    scanf("%d", &x);
    return  x;
}

llint lin() {
    llint x;
    scanf("%lld", &x);
    return  x;
}

double fin() {
    double  x;
    scanf("%lf", &x);
    return x;
}