#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
int x[17], y[17];
int main()
{
#ifdef LOCAL
	freopen("input.txt", "r", stdin);
#endif
	int q;
	scanf("%d", &q);
	for (int qq = 1; qq <= q; qq++)
	{
		int n;
		scanf("%d", &n);
		for (int i = 1; i <= n; i++)
		{
			scanf("%d %d", &x[i], &y[i]);
		}
		int minX = x[1], maxX = x[1], minY = y[1], maxY = y[1];
		for (int i = 1; i <= n; i++)
		{
			minX = min(minX, x[i]);
			maxX = max(maxX, x[i]);
			minY = min(minY, y[i]);
			maxY = max(maxY, y[i]);
		}
		bool ok = true;
		for (int i = 1; i <= n; i++)
		{
			bool c = false;
			bool onX = false, onY = false;
			bool inX = false, inY = false;
			if (x[i] == minX || x[i] == maxX) onX = true;
			if (y[i] == minY || y[i] == maxY) onY = true;
			if (x[i] >= minX && x[i] <= maxX) inX = true;
			if (y[i] >= minY && y[i] <= maxY) inY = true;
			if (onX && inY) c = true;
			if (onY && inX) c = true;
			if (!c) ok = false;

		}
		if (ok)
		{
			puts("YES");
		}
		else
		{
			puts("NO");
		}
	}
}