#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int diff(int a, int b) {
    if (a > b)
        return a-b;
    return b-a;
}
int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int q, n, x, y, i, a, b, dx, dy, u, v, flag;
    int p[10][2];
    scanf("%d", &q);
    while (q--) {
        scanf("%d", &n);
        for (i = 0; i < n; i++)
            scanf("%d%d", &p[i][0], &p[i][1]);
        if (n < 3) {
            printf("YES\n");
            continue;
        }
        x = p[0][0];
        y = p[0][1];
        a = p[1][0];
        b = p[1][1];
        dx = diff(x, a);
        dy = diff(y, b);
        u = dx>dy?dx:dy;
        flag = 0;
        for (i = 2; i < n; i++) {
            a = p[i][0];
            b = p[i][1];
            dx = diff(x, a);
            dy = diff(y, b);
            v = dx>dy?dx:dy;
            if (u != v) {
                flag = 1;
                break;
            }
        }
        if (flag == 0)
            printf("YES\n");
        else
            printf("NO\n");
    }
    return 0;
}