#include <bits/stdc++.h>

#define s1(n)                       scanf("%d",&n)
#define s2(n,m)                     scanf("%d%d",&n,&m)
#define s3(n,m,o)                   scanf("%d%d%d",&n,&m,&o)
#define sc(n)                       scanf("%c",&n)
#define sl(n)                       scanf("%ld",&n)
#define sll(n)                      scanf("%lld",&n)
#define sf(n)                       scanf("%lf",&n)
#define ss(n)                       scanf("%s",n)

#define bitcount                    __builtin_popcount
#define gcd                         __gcd

#define forall(i,a,b)               for(int i=a;i<b;i++)

int main()
{
    int q,n;
    s1(n);
    forall(j,0,n)
    {
    int a[10],b[10],x1,y1;
    bool yes=true,x=true,y=true;
    scanf("%d",&q);
        forall(i,0,q)
        {
            s2(a[i],b[i]);
            a[i]-=a[0];
            if (a[i]!=0)
            {
                if (x) { x1=a[i]; x=false; }
                else
                {
                    if (a[i]!=x1) { yes=false; break; }
                }
            }
            if (b[i]!=0)
            {
                if (y) { y1=b[i]; y=false; }
                else
                {
                    if (b[i]!=y1) { yes=false; break; }
                }
            }
        }
    if (yes) printf("YES\n");
    else printf("NO\n");
    }

    return 0;
}