# include<iostream>

# include<cstdio>

# include<map>

# include<vector>

# include<cstring>

# include<algorithm>

using namespace std;

# define mid (l+(r-l)/2)

const int N=1000;

void read(int &x)

{

    x=0;

    char c;

    while((c=getchar())&&(c<'0'||c>'9'));

    x=c-'0';

    while(c=getchar()){

        if(c<'0'||c>'9') break;

        x=x*10+c-'0';

    }

}

//*****************************************

struct Node

{

    int c;

    double len;

};

struct Segment

{

    double x1,x2,y;

    int d;

};

Segment seg[N*2+5];

map<double,int>mp;

vector<double>v;

Node tr[(N<<3)+5];

bool comp(const Segment &s1,const Segment &s2)

{

    return s1.y<s2.y;

}

void pushUp(int rt)

{

	tr[rt].len=tr[rt<<1].len+tr[rt<<1|1].len;

}

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

{

    tr[rt].c=0;

    tr[rt].len=0.0;

    if(l==r) return ;

    build(rt<<1,l,mid);

    build(rt<<1|1,mid+1,r);

}

void update(int rt,int l,int r,int L,int R,int d)

{

    if(l==r){

		tr[rt].c+=d;

		if(tr[rt].c>1) tr[rt].len=v[r]-v[l-1];

		else tr[rt].len=0;

	}else{

		if(L<=mid) update(rt<<1,l,mid,L,R,d);

		if(R>mid) update(rt<<1|1,mid+1,r,L,R,d);

		pushUp(rt);

	}

}

int main()

{

    //freopen("in.txt","r",stdin);

    int T,n;

    read(T);

    while(T--)

    {

        read(n);

        v.clear();

        mp.clear();

        double x1,x2,y1,y2;

        for(int i=0;i<n;++i){

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

            seg[i<<1].x1=seg[i<<1|1].x1=x1;

            seg[i<<1].x2=seg[i<<1|1].x2=x2;

            seg[i<<1].y=y1,seg[i<<1|1].y=y2;

            seg[i<<1].d=1,seg[i<<1|1].d=-1;

            v.push_back(x1);

            v.push_back(x2);

        }

        n<<=1;

        sort(seg,seg+n,comp);

        sort(v.begin(),v.end());

        int m=unique(v.begin(),v.end())-v.begin();

        for(int i=0;i<m;++i) mp[v[i]]=i+1;

        seg[n].y=seg[n-1].y;

        build(1,1,m-1);

        double ans=0.0;

        for(int i=0;i<n;++i){

            update(1,1,m-1,mp[seg[i].x1],mp[seg[i].x2]-1,seg[i].d);

            ans+=tr[1].len*(seg[i+1].y-seg[i].y);

			//cout<<tr[1].len<<endl;

        }

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

    }

    return 0;

}