#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
using namespace std;

int q,n,x[11],y[11];
vector<int>vx,vy;
set<int>X,Y;

int main() {
    scanf("%d",&q);
    while(q--){
        scanf("%d",&n);
        X.clear();
        Y.clear();
        vx.clear();
        vy.clear();
        for(int i=0; i<n; ++i){
            scanf("%d%d",&x[i],&y[i]);
            if(X.find(x[i])==X.end())vx.push_back(x[i]),X.insert(x[i]);
            if(Y.find(y[i])==Y.end())vy.push_back(y[i]),Y.insert(y[i]);
        }
        bool found=0;
        for(int i=0; i<vx.size(); ++i){
            for(int j=i+1; j<vx.size(); ++j)
                for(int h=0; h<vy.size(); ++h)
                    for(int k=h+1; k<vy.size(); ++k){
                        bool ok=1;
                        for(int t=0; t<n; ++t){
                            if(x[t]!=vx[i]&&x[t]!=vx[j]&&y[t]!=vy[h]&&y[t]!=vy[k])ok=0;
                            if((x[t]==vx[i]||x[t]==vx[j])&&(y[t]>max(vy[h],vy[k])||y[t]<min(vy[h],vy[k])))ok=0;
                            if((y[t]==vy[h]||y[t]==vy[k])&&(x[t]>max(vx[i],vx[j])||x[t]<min(vx[i],vx[j])))ok=0;
                        }
                        if(ok)found=1;
                    }
        }
        if(found)puts("YES");
        else puts("NO");
    }
}