#include <bits/stdc++.h>

using namespace std;

const int MAXN = 505;
const int INF = 50;

struct Snake {
  int x1, y1, x2, y2;
  Snake() {};
  Snake(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {
  	check();
  };
  void check() {
  	assert(x1 >= 1 && x1 <= INF);
    assert(y1 >= 1 && y1 <= INF);
    assert(x2 >= 1 && x2 <= INF);
    assert(y2 >= 1 && y2 <= INF);
    assert(x1 == x2 || y1 == y2);
    if (x1 > x2) {
  		swap(x1, x2);
  		swap(y1, y2);
  	} else if (y1 > y2) {
  		swap(x1, x2);
  		swap(y1, y2);
  	}
  }
  void read() {
    scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
    check();
  }
};

int distance(int x, int y, Snake s) {
	if (s.y1 == s.y2) {
		if (x > s.x1 && x <= s.x2) {
			return abs(s.y1 - y);
		}	
	}
	if (s.x1 == s.x2) {
		if (y >= s.y1 && y <= s.y2) {
			return abs(s.x1 - x);
		}	
	}
	int ans = min(abs(x - s.x1) + abs(y - s.y1), abs(x - s.x2) + abs(y - s.y2));
	return ans;
}

int main() {
	/*
	Snake s(2, 2, 2, 2);
	cout << distance(1, 1, s) << endl;
	*/
	int T;
	scanf("%d", &T);
	assert(T >= 1 && T <= 50);
	while (T--) {
		int n;
		cin >> n;
		assert(n >= 1 && n <= 50);
		vector<Snake> snakes(n);
		for (int i = 0; i < n; i++) {
			snakes[i].read();
		}
		int ans = (int) 1e9;
		const int LARGE = 100;
		for (int x = 1; x <= LARGE; x++) {
			for (int y = 1; y <= LARGE; y++) {
				int mx = 0;
				for (int i = 0; i < n; i++) {
					mx = max(mx, distance(x, y, snakes[i]));
				}
				//cerr << x << " " << y << " " << mx << endl;
				ans = min(ans, mx);
			}
		}
		cout << ans << endl;
	}
	return 0;
}