#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>

using namespace std;

int main() {
    int T;
    scanf("%d", &T);
    while(T--){
        int N;
        scanf("%d", &N);
        pair<int, int> A[20];
        int X[20], Y[20];
        for(int i=1; i<=N; ++i){
            scanf("%d %d", &A[i].first, &A[i].second);
            X[i] = A[i].first, Y[i] = A[i].second;
        }
        sort(X + 1, X + N + 1);
        sort(Y + 1, Y + N + 1);
        int x0 = X[1], x1 = X[N], y0 = Y[1], y1 = Y[N];
        bool ok = true;
        for(int i=1; i<=N; ++i){
            int xx = A[i].first, yy = A[i].second;
            if((x0 <= xx && xx <= x1 && (yy == y0 || yy == y1)) || (y0 <= yy && yy <= y1 && (xx == x0 || xx == x1))) continue;
            else{ ok = false; break; }
        }
        printf("%s\n", ok ? "YES" : "NO");
    }
    return 0;
}