function processData(input) {
    var lines = input.split("\n");
    var q = parseInt(lines[0]);
    var n = 0;
    var tmp;
    var t = [];
    var cur = 1;
    for (var i = 0; i < q; i++) {
        n = parseInt(lines[cur]);
        cur++;
        t = [];
        for(var j = 0; j < n; j++) {
            tmp = lines[cur].split(' ');
            cur++;
            t[j] = [];
            t[j][0] = parseInt(tmp[0]);
            t[j][1] = parseInt(tmp[1]);
        }
        console.log(sol(n, t));
        
    }
} 


function sol(n, t) {
    if (n <= 2) return "YES";
    var slope = 1.389;
    for (var k = 1; k < n; k++) {
       if (t[k][0] == t[0][0] || t[k][1] == t[0][1] || slope == 1.389) {
           //console.error("good");
           if (t[k][0] != t[0][0] && t[k][1] != t[0][1]) slope = (t[k][1] - t[0][1]) / (t[k][0] - t[0][0]);
       }
       else if ((t[k][1] - t[0][1]) / (t[k][0] - t[0][0]) != slope) return "NO";
        
    }
    return "YES";
    
    
}

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

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