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

typedef struct{ int x, y; }P;
P A[ 12 ];
int n;

int min( int a , int b){ return ( a < b )?a:b; }
int max( int a, int b ){ return ( a > b )?a:b; }
int inside( int xmin, int xmax, int ymin, int ymax, int x, int y){
    
    if( xmin < x && x < xmax && ymin < y && y < ymax ) return 1;
    return 0;
        
}
    

int main() {
   int test;
    
    scanf("%d", &test);
    
    for( ; test--; ){
    scanf("%d", &n );
    
    for( int i = 0; i<n; i++ ) scanf("%d %d", &A[ i].x, &A[ i].y);
    
    int ban = 1;
    
    for( int i = 0; i<n; i++ )
        for( int j = 0; j<n; j++)
           for( int k = 0; k<n; k++ )
              if( i != j && i != k && j != k )
                 if( inside( min( A[i].x, A[ j ].x ), max( A[i].x, A[j].x), min( A[ i].y, A[ j ].y), max( A[ i ].y, A[ j ].y), A[ k].x, A[ k ].y ) ) {ban = 0; break;}
        
        printf("%s\n", (ban)?"YES":"NO");}
    
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}