#include <bits/stdc++.h>
using namespace std;
typedef long long int LL;
typedef unsigned long long int uLL;
inline int _Int() { int x; scanf("%d",&x); return x; }
LL bigMod(LL A,LL P,int M){ LL R=1; for(A%=M; P; P>>=1) { if(P&1) R=(R*A)%M; A=(A*A)%M; } return R; } /** (A^P) % M **/
LL bigMul(LL A,LL B,LL M) { LL R=0; for(A%=M; B; B>>=1) { if(B&1) R=(R+A)%M; A=(A+A)%M; } return R; } /** (A*B) % M **/
LL negMod(LL A,LL B) { return ( ( ( A % B ) + B) % B ); } /** (A % B) when A is negative or positive **/
uLL _pow(uLL A,int P) { uLL R=1; for(; P; P>>=1) { if(P&1) R=(R*A); A=(A*A); } return R; } /** (A^P) **/
template<class T>T GCD(T x, T y) { while(x) x^=y^=x^=y%=x; return y; } /** GCD(a,b) **/
#define pi   acos(-1)
#define pb   push_back
#define endl '\n'
/*************************************************************************************************************************
**                                            Syed Zafrul Lipu (ShockProof)                                              *
**                                            CSE, University of Asia Pacific                                            *
**************************************************************************************************************************/

struct Point{
    LL x,y;

};


Point L[12];

bool inRng( LL left, LL mid, LL right )
{
    return left <= mid && mid <= right ;
}

void Main()
{
    int n=_Int();
    for(int i=0; i<n; i++) {
        L[i].x = _Int();
        L[i].y = _Int();
    }

    LL x = L[0].x, y = L[0].y;
    LL p = L[0].x, q = L[0].y;

    for(int i=0; i<n; i++) {
        x = min( x, L[i].x );
        y = min( y, L[i].y );
        p = max( p, L[i].x );
        q = max( q, L[i].y );
    }

    for(int i=0; i<n; i++) {
        bool flag = 0;
        if( L[i].y == y && inRng( x , L[i].x , p ) ) flag = 1;
        if( L[i].y == q && inRng( x , L[i].x , p ) ) flag = 1;
        if( L[i].x == x && inRng( y , L[i].y , q ) ) flag = 1;
        if( L[i].x == p && inRng( y , L[i].y , q ) ) flag = 1;
        if( !flag ) {
            printf("NO\n");
            return;
        }
    }
    printf("YES\n");
}

int main()
{
    int test = _Int();
    while(test--) {
        Main();
    }
    return 0;
}