#include<map>
#include<set>
#include<ctime>
#include<cmath>
#include<stack>
#include<queue>
#include<string>
#include<vector>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#define first fi
#define second se
#define lowbit(x) (x & (-x))typedef unsigned long long int ull;
typedef long long int ll;
const double pi = 4.0*atan(1.0);
const int inf = 0x3f3f3f3f;
const int maxn = 2005;
const int maxm = 305;
using namespace std;int n, m, tol, T;
struct Node{double l, r, h;int f;bool operator < (Node a) const {return h < a.h;}
};
Node node[maxn];
double a[maxn];
int cnt[maxn << 2];
double sum1[maxn << 2];
double sum2[maxn << 2];void init() {memset(a, 0, sizeof a);memset(cnt, 0, sizeof cnt);memset(sum1, 0, sizeof sum1);memset(sum2, 0, sizeof sum2);memset(node, 0, sizeof node);
}void pushup(int left, int right, int root) {if(cnt[root] >= 2) {sum2[root] = sum1[root] = a[right+1] - a[left];} else if(cnt[root] == 1) {sum1[root] = a[right+1] - a[left];if(left == right)    sum2[root] = 0;else    sum2[root] = sum1[root << 1] + sum1[root << 1 | 1];} else {if(left == right)    sum1[root] = sum2[root] = 0;else {sum1[root] = sum1[root << 1] + sum1[root << 1 | 1];sum2[root] = sum2[root << 1] + sum2[root << 1 | 1];}}
}void update(int left, int right, int prel, int prer, int val, int root) {if(prel <= left && right <= prer) {cnt[root] += val;pushup(left, right, root);return ;}int mid = (left + right) >> 1;if(prel <= mid)    update(left, mid, prel, prer, val, root << 1);if(prer > mid)    update(mid+1, right, prel, prer, val, root << 1 | 1);pushup(left, right, root);return ;
}int main() {scanf("%d", &T);while(T--) {init();scanf("%d", &n);double x1, y1, x2, y2;for(int i=1; i<=n; i++) {scanf("%lf%lf%lf%lf", &x1, &y1, &x2, &y2);node[2*i].l = node[2*i-1].l = x1;node[2*i].r = node[2*i-1].r = x2;node[2*i].h = y1, node[2*i-1].h = y2;node[2*i].f = 1, node[2*i-1].f = -1;a[2*i] = x1, a[2*i-1] = x2;}n <<= 1;sort(node+1, node+1+n);sort(a+1, a+1+n);int nn = unique(a+1, a+1+n) - (a+1);double ans = 0.0;for(int i=1; i<n; i++) {int l = lower_bound(a+1, a+1+nn, node[i].l) - a;int r = lower_bound(a+1, a+1+nn, node[i].r) - a;update(1, nn, l, r-1, node[i].f, 1);ans += sum2[1] * (node[i+1].h - node[i].h);}printf("%.2f\n", ans);}return 0;
}