#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<utility>
#include<set>
#include<stack>
#include<list>
#include<deque>
#include<bitset>
#include<iomanip>
#include<cstring>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<climits>
#include<cmath>
#include<cctype>


#define pb push_back
#define mp make_pair
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define ren(i,a,b) for(int i=a;i>=b;i--)
#define ff first
#define ss second
#define pll pair<long long int,long long int>
#define pii pair<int,int>
#define vll vector<long long int>
#define vii vector<int>
#define gi(n) scanf("%d",&n)
#define gll(n) scanf("%lld",&n)
#define gstr(n) scanf("%s",n)
#define gl(n) cin >> n
#define oi(n) printf("%d",n)
#define oll(n) printf("%lld",n)
#define ostr(n) printf("%s",n)
#define ol(n) cout << n
#define os cout<<" "
#define on cout<<"\n"
#define o2(a,b) cout<<a<<" "<<b
#define all(n) n.begin(),n.end()
#define present(s,x) (s.find(x) != s.end())
#define cpresent(s,x) (find(all(s),x) != s.end())
#define tr(container, it) for(__typeof(container.begin()) it = container.begin(); it != container.end(); it++)
using namespace std;

typedef unsigned long long int ull;
typedef long long int ll;
typedef vector<vector<ll> > mat;

int main()
{ios_base::sync_with_stdio(false);
int t;
gl(t);
while(t--)
{
	int n,x[15],y[15];
	cin>>n;
	rep(i,0,n-1)cin>>x[i]>>y[i];
	int foo=0;
    x[n]=1e5;y[n]=1e5;n++;
	rep(i,0,n-1)
	{
		rep(j,0,n-1)
		{
			if(x[i]!=x[j])
			{
				rep(k,0,n-1)
				{
					rep(l,0,n-1)
					{
						if(y[k]!=y[l])
						{
                     
							int x1=x[i],x2=x[j],y1=y[k],y2=y[l];
							if(x1>x2)swap(x1,x2);
							if(y1>y2)swap(y1,y2);
							int cc=0;
							rep(ii,0,n-2)
							{
								if(x[ii]==x1&&y[ii]>=y1&&y[ii]<=y2)cc++;
								else if(x[ii]==x2&&y[ii]>=y1&&y[ii]<=y2)cc++;
								else if(y[ii]==y1&&x[ii]>=x1&&x[ii]<=x2)cc++;
								else if(y[ii]==y2&&x[ii]>=x1&&x[ii]<=x2)cc++;
							}
							if(cc==n-1)foo=1;
						}
					}
				}
			}
		}
	}
	if(foo)ol("YES\n");
	else ol("NO\n");
}
return 0;
}