#include<iostream>
#include<algorithm>
using namespace std;

#define x first
#define y second

typedef pair<int , int> POINT2D;

POINT2D v[12],vec[12];

int inline crossprod2D(const POINT2D &p1, const POINT2D &p2, const POINT2D &p3)
{
	return (p2.x - p1.x)*(p3.y - p1.y) - (p2.y - p1.y)*(p3.x - p1.x);
}

int inline dotprod2D(const POINT2D &p1, const POINT2D &p2, const POINT2D &p3)
{
	return (p2.x - p1.x)*(p3.x - p2.x) + (p2.y - p1.y)*(p3.y - p2.y);
}

bool compare(const POINT2D &p1, const POINT2D &p2)
{
	if (crossprod2D(v[1], p1, p2) > 0)
		return 1;
	else
		return 0;
}


int main()
{
	int q;

	cin >> q;

	for (int j = 1;j <= q;++j)
	{
		int el, nr = 0;

		int N;

		cin >> N;

		for (int i = 1;i <= N;++i)
			cin >> v[i].x >> v[i].y;
        
		if (N <= 2)
		{
			cout << "YES\n";
			continue;
		}
		else if (N == 3)
		{
			if (dotprod2D(v[1], v[2], v[3]) == 0 || dotprod2D(v[1], v[3], v[2]) == 0 || dotprod2D(v[2], v[1], v[3]) == 0 ||
				dotprod2D(v[2], v[3], v[1]) == 0 || dotprod2D(v[3], v[1], v[2]) == 0 || dotprod2D(v[3], v[2], v[1]) == 0 ||
				crossprod2D(v[1], v[2], v[3]) == 0 || crossprod2D(v[1], v[3], v[2]) == 0 || crossprod2D(v[2], v[1], v[3]) == 0 ||
				crossprod2D(v[2], v[3], v[1]) == 0 || crossprod2D(v[3], v[1], v[2]) == 0 || crossprod2D(v[3], v[2], v[1]) == 0)
				cout << "YES\n";
			else
				cout << "NO\n";
			continue;
		}

		int y_min = v[1].y;
		el = 1;
		for (int i = 2;i <= N;++i)
			if (v[i].y < y_min)
			{
				el = i;
				y_min = v[i].y;
			}

		swap(v[el], v[1]);

		sort(v + 2, v + N + 1, compare);

		vec[++nr] = v[1];
		vec[++nr] = v[2];


		int c = 0,i;
		for (i = 3;i <= N;++i)
		{
			if (crossprod2D(vec[nr - 1], vec[nr], v[i]) < 0)
			{
				cout << "NO\n";
				break;
			}
			else if (crossprod2D(vec[nr - 1], vec[nr], v[i]) > 0 && dotprod2D(vec[nr - 1], vec[nr], v[i]) != 0)
			{
				cout << "NO\n";
				break;
			}
			else if (crossprod2D(vec[nr - 1], vec[nr], v[i]) > 0 && dotprod2D(vec[nr - 1], vec[nr], v[i]) == 0)
			  ++c;

			vec[++nr] = v[i];
		}

		if (i>N)
			cout << "YES\n";

	}

	return 0;
}