#include<cstdio>

#include<map>

#include<algorithm>

using namespace std;

const int N=;

struct Node

{

    double x,yl,yh;

    int w;

    bool operator<(Node t)const

    {

        return x<t.x;

    }

}edge[N];

struct

{

    int l,r,cover;

}tr[N];

double ys[N];

void build(int u,int l,int r)

{

    int mid=l+r>>;

    tr[u].l=l,tr[u].r=r;

    tr[u].cover=;

    if (r-l>)

    {

        build(u<<,l,mid);

        build(u<<|,mid,r);

    }

}

void modify(int u,int l,int r,int val)

{

    int mid=tr[u].l+tr[u].r>>;

    if(tr[u].l==l&&tr[u].r==r)

    {

        tr[u].cover+=val;

    }

    else if(tr[u].r-tr[u].l>)

    {

        if (l>=mid)

            modify(u<<|,l,r,val);

        else if(r<=mid)

            modify(u<<,l,r,val);

        else

        {

            modify(u<<,l,mid,val);

            modify(u<<|,mid,r,val);

        }

    }

}

void query(int root,double &ans)

{

    //如果被覆盖次数大于1

    if (tr[root].cover>)

        ans+=ys[tr[root].r]-ys[tr[root].l];

    //上式不满足时，可能往下的子区间满足，就往下递归

    //如果不是叶节点

    else if(tr[root].r-tr[root].l>)

    {

        tr[root<<].cover+=tr[root].cover;

        tr[root<<|].cover+=tr[root].cover;

        tr[root].cover=;

        query(root<<,ans);

        query(root<<|,ans);

    }

}

int main()

{

    int T,N;

    double x1,x2,y1,y2,ans,res;

    scanf("%d",&T);

    while(T--)

    {

        res=;

        map<double,int>mp;

        scanf("%d",&N);

        for (int i=,j=;i<=N;++i,j+=)

        {

            scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);

            //入边

            edge[j].x=x1,edge[j].yl=y1,edge[j].yh=y2;

            edge[j].w=;

            //出边

            edge[j+].x=x2,edge[j+].yl=y1,edge[j+].yh=y2;

            edge[j+].w=-;

            //扫描线

            ys[j]=y1,ys[j+]=y2;

        }

        //按x排序

        sort(edge+,edge++*N);

        //y离散化

        sort(ys+,ys++*N);

        int cnt=unique(ys+,ys++*N)-(ys+);

        build(,,cnt);

        //离散化

        //映射之后的编号 ，查询的实话再映射到ys中去

        for (int i=;i<=cnt;++i)

            mp[ys[i]]=i;

        for (int i=;i<*N;++i)

        {

            ans=;

            //插进去

            modify(,mp[edge[i].yl],mp[edge[i].yh],edge[i].w);

            query(,ans);

            res+=ans*(edge[i+].x-edge[i].x);

        }

        printf("%.2lf\n",res);

    }

    return ;

}