/*
    Towhidul Islam
    University Of Dhaka
    Problem Name :
    Algorithm Used :
*/

#include<bits/stdc++.h>

typedef long long ll;

#define SSTR(x)         dynamic_cast< ostringstream & >( \
                        (ostringstream() << dec << x )).str()
#define pb              push_back
#define mem(a, x)       memset(a, x, sizeof a)
#define PI              acos(-1)
#define all(a)          a.begin(), a.end()
#define ff              first
#define ss              second
#define read(in)        freopen("in.txt", "r", stdin)
#define write(out)      freopen("out.txt", "w", stdout)
#define INF             1<<30
#define eps             1e-9
#define FORN(i, n)      for(int i = 0; i < n; i++)
#define FORAB(i, x, n)  for(int i = x; i < n; i++)
#define FORD(i, x, n)   for(int i= n - 1; i >= x; i--)
#define scan(n)         scanf("%d", &n)
#define print(n)        printf("%d\n", n)
#define DBG(x)          cerr<<#x<<" : "<<x<<endl
#define DBGII(x, y)     cerr<<#x<<" : "<<x<<" "<<#y<<" : "<<y<<endl
#define DBGVEC(v, n)    FORAB(i, 0, n) { cout<<v[i]<<" "; } cout<<"\n"
#define chkwhere        cerr<<"LOL\n"
#define pii             pair<int, int>
#define MOD             1000000007
#define MAX             1000007

int Set(int N, int pos) { return N = N | (1 << pos); }
int reSet(int N, int pos) { return N = N & ~(1 << pos); }
bool check(int N, int pos) { return (bool)(N & (1 << pos)); }

using namespace std;

pii p[11];
int main() {
    // read(in);
    // write(out);
    int x, y, q, n;
    scan(q);
    while(q--){
        int xmx = -10001, ymx = -10001, xmn = 10001, ymn = 10001;
        scan(n);
        FORAB(i, 0, n){
            scan(x);
            scan(y);
            p[i] = pii(x, y);
            xmx = max(xmx, x);
            xmn = min(xmn, x);
            ymx = max(ymx, y);
            ymn = min(ymn, y);
        }

        // DBGII(xmx, ymx);
        // DBGII(xmn, ymn);
        //if(xmx != xmn && ymx != ymn){
            bool f = true;
            FORAB(i, 0, n){
                x = p[i].ff;
                y = p[i].ss;

                bool tmp = false;
                if(x == xmx || x == xmn){
                    if(y >= ymn && y <= ymx){
                        tmp = true;
                    }
                }
                if(y == ymx || y == ymn){
                    if(x >= xmn && x <= xmx){
                        tmp = true;
                    }
                }
                if(!tmp){
                    f = false;
                    break;
                }
            }
            if(f) puts("YES");
            else puts("NO");
//        }
//        else{
//            puts("NO");
//        }
    }
    return 0;
}