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


int main() {
    int q;
     int n;
    cin >> q;
    int x, y;
    int arrX[20], arrY[20];
    // int x1, x2, y1, y2;
    while(q--) {
        // x1 = x2 = y1 = y2 = -100000;
        int MinX = INT_MAX, MaxX = INT_MIN;
        int MinY = INT_MAX, MaxY = INT_MIN;
        cin >> n;
        if(n < 3) {for(int i = 0; i < n; ++i) { cin >> x >> y; }  cout << "YES\n"; continue;}
        bool yes = true;
        for(int i = 0; i < n; ++i) {
            cin >> x >> y;
            arrX[i] = x; arrY[i] = y;
            MinX = min(MinX, x);MinY = min(MinY, y);MaxX = max(MaxX, x);MaxY = max(MaxY, y);
        }
        for(int i = 0; i < n; ++i) {
            if(arrX[i] != MinX and arrX[i] != MaxX and arrY[i] != MinY and arrY[i] != MaxY) {
                yes = false;
                break;
            }
            if(arrX[i] == MinX or arrX[i] == MaxX) {
                if(arrY[i] < MinY or arrY[i] > MaxY) {
                    yes = false;
                    break;
                }    
            }
            
            if(arrY[i] == MinY or arrY[i] == MaxY) {
                if(arrX[i] < MinX or arrX[i] > MaxX) {
                    yes = false;
                    break;
                }
            }
        }
        if(yes) {cout << "YES\n"; }
        else cout << "NO\n";
    }
    return 0;
}