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#include <bits/stdc++.h>

using namespace std;
long long k,n,i,j,u,t,w,xp,xs,ax,ay;
int z,pp;
long long m,k1,k2,k3,k4;
vector<long long> x;
long long v[4000005];
long long f[4000005];
long long fv[4000005];
long long p[4000005];
long long pv[4000005];
int a[2000005];
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	m=1e9+7;
	v[1] = 1;
	for (i = 2; i <4000005LL; i++) 
	    v[i] = (m - (m / i) * v[m % i] % m) % m;

	f[0]=1;
	p[0]=1;
	pv[0]=1;
	fv[0]=1;
	for(i=1;i<=4000000LL;i++) {
		f[i]=(f[i-1]*i)%m;
		fv[i]=(fv[i-1]*v[i])%m; 
		p[i]=(p[i-1]<<1LL)%m;
		pv[i]=(pv[i-1]*v[2])%m;
	}

	cin >> t;
	for(u=0;u<t;u++) {
		cin >> n;
	z=0;
	x={};
	w=0;
	for(i=0;i<2*n;i++) {
		cin >> j; 
		a[i]=j;
		if(j==2 and w==0) {w=1; pp=i;}
		if(j==0 and w==0) {w=-1; pp=i;}
		if(w==1 and j==0) w=-3;
		if(w==-1 and j==2) w=-3;
		if(j==1){
			if(z<=0) z--;
			else {if(z!=0) x.push_back(z); z=-1;}
		}
		if(j==2 or j==0) {
			if(z>=0) z++;
			else {if(z!=0) x.push_back(z); z=1;};
		}
	}
	x.push_back(z);
	if(x.size()>1 and x[0]*x[x.size()-1]>0) {
		x[0]+=x[x.size()-1];
		if(pp==0) {
			for(i=2*n-1;(a[i]==0 || a[i]==2);i--);
			pp=i+1;	
		}
		x.pop_back();
		
	}
	if(x.size()>1)
	for(auto xx:x) {if(xx%2==0) w=-3;}	
	if(w==-3) cout  << "0\n";
	else if(w==0) {
		k=(((((2*n*n)%m)*((f[4*n-3]*pv[2*n-2])%m))%m)*(2*n-1))%m;
		cout << k << '\n';
		//cout << (((256223893LL*fv[4*n-3])%m)*p[2*n-2])%m << '\n';
		continue;
	}
	else{
		//for(auto xx:x)
		//cout << xx <<' ';
		//cout << '\n';
		//cout << pp << "PP\n";	
		if(x.size()==1) {
			//cout  << ((f[4*n-2]*pv[2*n-1])%m) << '\n';
			//cout << ((n*(2*n-1))%m) << '\n';
			k=(f[4*n-2]*pv[2*n-1])%m;
			k*=(n*(2*n-1))%m;
			k%=m;
			cout << k << "\n"; continue;}
		if((pp%2 and w==1) or (pp%2==0 and w==-1)) { cout << 0 <<"\n"; continue;}
		k1=0;
		k2=0;
		k3=0;
		k4=0;
		xs=x.size()/2;
		for(auto xx: x) {
			if(xx<0){
				xp=-xx/2;
				ax=((f[4*n-2*xs-2]*pv[2*n-2*xs-1])%m); 
				ax*=((xp*xs)%m);
				k1+=ax%m; //xp*xs*f[4*n-2*xs-2]*pv[2*n-2*xs-1];
				k1%=m;
				if(n>xs) {
					ax=(f[4*n-2*xs-2]*pv[2*n-2*xs-2])%m;
					ax*=(n-xs+(m-((xp+1)*pv[1])%m))%m;
					ax%=m;
				k1+=(xp*ax)%m; //xp*(n-xs-(xp+1)*pv[2])*f[4*n-2*xs-2]*pv[2*n-2*xs-2];
				k1%=m;
				}
				if(n>xs) {
					ax=(f[4*n-2*xs-3]*pv[2*n-2*xs-1])%m;
					ax*=(xp*(xp+1))%m;
					ax%=m;
				k2+=((xs+1)*ax); //(xs+1)*xp*(xp+1)*f[4*n-2*xs-3]*pv[2*n-2*xs];
				k2%=m;
			}
				if(n>xs+1){
					ax=(f[4*n-2*xs-3]*pv[2*n-2*xs-2])%m;
					ax*=(xp*(xp+1))%m;
					ax%=m;
				k2+=(n-xs-1)*ax; //(n-xs-1)*xp*(xp+1)*f[4*n-xs-3]*pv[2*n-2*xs-1];
				k2%=m;
			}
			}
			else {
				xp=xx/2;
				ax=(f[4*n-2*xs-1]*pv[2*n-2*xs])%m;
				k3+=xs*ax; //xs*f[4*n-2*xs-1]*pv[2*n-2*xs];
				k3%=m;
				if(n>xs){
					ax=(f[4*n-2*xs-1]*pv[2*n-2*xs-1])%m;
				k3+=(n-xp-xs)*ax; //(n-xp-xs)*f[4*n-2*xs-1]*pv[2*n-2*xs-1];
				k3%=m;
			}
				if(n>xs){
					ax=(f[4*n-2*xs-2]*pv[2*n-2*xs-1])%m;
					ax*=((xs+1)*xp)%m;
					ax%=m;
				k4+=ax; //(xs+1)*xp*f[4*n-2*xs-2]*pv[2*n-2*xs-1];
				k4%=m;
				}
				if(n>xs+1){
					ax=(f[4*n-2*xs-2]*pv[2*n-2*xs-2])%m;
					ax*=((n-xs-1)*xp)%m;
					ax%=m;
				k4+=ax;//(n-xs-1)*xp*f[4*n-xs-2]*pv[2*n-2*xs-2];
				k4%=m;
			}
				
			}				
		}
		//cout << k1 <<  ' '<< k2 << ' ' << k3 << ' ' << k4 << '\n';
		cout << (k1+k2+k3+k4)%m << '\n';
		//if((k1+k2+k3+k4)%m==126000)  {
		//for(j=0;j<2*n;j++) cout << a[j] << ' ';
		//cout << '\n';
		//return 0;
		//}
	}
	
	}
}