#include <bits/stdc++.h>
using namespace std;
const int N = 11;
int x[N], y[N];
bool mpX[30000], mpY[30000];
int main() {
    int q;
    scanf("%d", &q);
    while(q--) {
        bool ok = false;
        int n;
        scanf("%d", &n);
        for (int i = 0; i < n; i++) {
            scanf("%d %d", &x[i], &y[i]);
        }
        for (int i = 0; i < n && !ok; i++) {
            for (int j = i; j < n && !ok; j++) {
                for (int ii = 0; ii < n && !ok; ii++) {
                    for (int jj = ii; jj < n && !ok; jj++) {

                        int X1 = min(x[i], x[j]), X2 = max(x[i], x[j]), Y1 = min(y[jj], y[ii]), Y2 = max(y[ii], y[jj]);
                        bool b = true;
                        for (int k = 0; k < n && !ok; k++) {
                            bool b1 = (x[k] == X1 || x[k] == X2) && (y[k] >= Y1 && y[k] <= Y2);
                               b1 |=  (y[k] == Y1 || y[k] == Y2) && (x[k] >= X1 && x[k] <= X2);
                            b &= b1;
                        }
                        if (b) {
                            ok = true;
                            break;
                        }
                    }
                }
            }
        }
        if (ok)
            puts("YES");
        else
            puts("NO");
    }
}