function processData(input) {
    //Enter your code here
    var arr = input.split(/\s+/g);
    var pointer = 0
    var q = arr[pointer++];
    for(var i = 0; i < q; i++){
        n = arr[pointer++];
        var x1,x2,y1,y2;
        var x = [],y = [];
        for(var j = 0;j<n;j++){
            x.push(parseInt(arr[pointer++]));
            y.push(parseInt(arr[pointer++]));
            if(!x1){
                x1 = x[j];
            }
            if(!x2){
                x2 = x[j];
            }
            if(!y1){
                y1 = y[j];
            }
            if(!y2){
                y2 = y[j];
            }
            if(x1 < x[j]){
                x1 = x[j];
            }
            if(x2 > x[j]){
                x2 = x[j];
            }
            if(y1 < y[j]){
                y1 = y[j];
            }
            if(y2 > y[j]){
                y2 = y[j];
            }
        }
        var flag = true;
        for(var j = 0;j<n;j++){
           if(x[j] != x1 && x[j] != x2 && y[j] != y1 && y[j] != y2){
               flag = false;
               break;
           }
        }
        flag?console.log('YES'):console.log('NO');
    }
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});