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#include <cstdio>
#include <vector>

using namespace std;

// #define dprint(...) printf(__VA_ARGS__)
#define dprint(...)

const int M = 1000000007;
typedef long long LL;

LL mul(LL a, LL b) {
  return (a*b)%M;
}

LL add(LL a, LL b) { return (a+b)%M; }
LL pow(LL a, int k) {
  if (k == 0) return 1;
  LL b = pow(mul(a, a), k/2);
  if (k % 2) return mul(b, a); else return b;
}
LL inv(LL a) { return pow(a, M-2); }
LL div1(LL a, LL b) { return mul(a, inv(b)); }
LL div2(LL a) { return mul(a, (M+1)/2); }

void work() {
  int n; scanf("%d", &n);

  // kombinacje na karty rozlozone pozostalym tylu osobom
  vector<LL> dist(n*2+1);
  vector<LL> fact(n*4+1);

  dist[0] = 1;
  for (int i=1; i<=n*2; ++i) {
    dist[i] = mul(dist[i-1], div2(mul(i*2, i*2-1)));
  }
  fact[0] = 1;
  for (int i=1; i<=n*4; ++i) {
    fact[i] = mul(fact[i-1], i);
  }

  vector<int> a(n*2);
  vector<int> cnt(3);
  for (int i=0; i<n*2; ++i) {
    scanf("%d", &a[i]);
    cnt[a[i]]++;
  }

  if (cnt[0] > 0 && cnt[2] > 0) {
    printf("0\n");
    return;
  }
 
  // zawsze jedna strona
  if (cnt[1] == 0) {
    LL res = 0;

    // dwie najwyzsze u roznych osob
    if (n > 1) {
      LL res2 = mul(n, n-1);
      res2 = mul(res2, mul(4*n-2, 4*n-3));
      res2 = mul(res2, dist[2*n-2]);
      res = add(res, res2);
    }
 
    // dwie najwyzsze u jednej osoby
    LL res1 = mul(n, dist[2*n-1]);
    res = add(res, res1);

    printf("%lld\n", res);
    return;
  }

  // same remisy
  if (cnt[0] == 0 && cnt[2] == 0) {
    LL res = 0;
 
    // drugie najwyzsze u roznych osob
    if (n > 1) {
      LL res1 = mul(n, mul(n, n-1));
      res1 = mul(res1, mul(n*4-3, mul(n*4-4, n*4-5)));
      res1 = mul(res1, dist[n*2-3]);
      res = add(res, res1);
    }

    // drugie najwyzsze u jednej osoby
    LL res2 = mul(n, mul(n, n*4-3));
    res2 = mul(res2, dist[n*2-2]);
    res = add(res, res2);

    res = mul(res, 2);
    printf("%lld\n", res);
    return;
  }

  vector<int> wins, ties;
  for (int i=0; i<n*2; ++i) {
    if (a[i] == 1) {
      if (i == 0 || a[i] != a[i-1]) ties.push_back(1);
      else ties.back()++;
    } else {
      if (i == 0 || a[i] != a[i-1]) wins.push_back(1);
      else wins.back()++;
    }
  }

  for (int i=1; i<n*2; ++i) {
    if (a[i] != a[i-1]) {
      if (a[i] == 1) {
        if ((a[i-1] == 2) ^ (i%2 == 1)) {
          printf("0\n");
          return;
        }
      }
      if (a[i-1] == 1) {
        if ((a[i] == 2) ^ (i%2 == 0)) {
          printf("0\n");
          return;
        }
      }
    }
  }

  if (wins.size() > ties.size()) {
    wins[0] += wins.back();
    wins.pop_back();
  }

  if (ties.size() > wins.size()) {
    ties[0] += ties.back();
    ties.pop_back();
  }

  if (a[0] == 1) {
    ties.push_back(ties[0]);
    ties.erase(ties.begin());
  }
 /* 
  printf("Ties: ");
  for (int c: ties) printf("%d ", c);
  printf("\nWins: ");
  for (int c: wins) printf("%d ", c);
  printf("\n");
*/
  bool bad = false;
  for (int c: ties) if (c%2==0) bad = true;
  for (int c: wins) if (c%2==0) bad = true;
  if (bad) {
    printf("0\n");
    return;
  }

  int k = wins.size();
  LL res = 0;
  for (int i=0; i<k; ++i) {

    // krok wstecz
 
    // nie pokrywa sie
    if (n-wins[i]/2 > k) {
      LL res1 = mul( n-wins[i]/2-k , div1(fact[n*4-k*2-1], fact[n*4-k*4-2]));
      res1 = mul(res1, dist[n*2-k*2-1]);
      res = add(res, res1);
    }

    // pokrywa sie
    LL res2 = mul(k, div1(fact[n*4-k*2-1], fact[n*4-k*4]));
    res2 = mul(res2, dist[n*2-k*2]);
    res = add(res, res2);

    // dwa takie same
    if (wins[i] > 1) {
      // nie pokrywa sie
      LL res3 = mul( wins[i]/2 , mul( n-k-1, div1(fact[n*4-k*2-2], fact[n*4-k*4-4])));
      res3 = mul(res3, dist[n*2-k*2-2]);
      res = add(res, res3);

      // pokrywa sie
      LL res4 = mul( wins[i]/2 , mul( k+1, div1(fact[n*4-k*2-2], fact[n*4-k*4-2])));
      res4 = mul(res4, dist[n*2-k*2-1]);
      res = add(res, res4);
    }
  }
    
  dprint("Kuku2\n");

  wins.push_back(wins[0]);
  wins.erase(wins.begin());
  
  for (int i=0; i<k; ++i) {

    if (ties[i] > 1) {
      // krok wstecz

      dprint("res1\n");

      // nie pokrywa sie
      LL res1 = mul(n - ties[i]/2 - k, ties[i]/2);
      if (ties[i] > 1) {
        res1 = add(res1, div2(mul(ties[i]/2, ties[i]/2-1)));
      }
      res1 = mul(res1, div1(fact[n*4-k*2-2], fact[n*4-k*4-4]));
      res1 = mul(res1, dist[n*2-k*2-2]);
      res = add(res, res1);

      dprint("res2\n");

      // pokrywa sie
      LL res2 = mul(mul( ties[i]/2, k ), div1(fact[n*4-k*2-2], fact[n*4-k*4-2]));
      res2 = mul(res2, dist[n*2-k*2-1]);
      res = add(res, res2);

      // dwa takie same
      
      if (n*4-k*4-6 >= 0) {
        dprint("res3\n");
        // nie pokrywa sie
        LL res3 = mul( div2(mul(ties[i]/2, (ties[i]+1)/2)), mul(n-k-1, div1(fact[n*4-k*2-3], fact[n*4-k*4-6])));
        res3 = mul(res3, dist[n*2-k*2-3]);
        res = add(res, res3);
      }
      dprint("res4\n");
      
      // pokrywa sie
      LL res4 = mul( div2(mul(ties[i]/2, (ties[i]+1)/2)), mul( k+1, div1(fact[n*4-k*2-3], fact[n*4-k*4-4])));
      res4 = mul(res4, dist[n*2-k*2-2]);
      res = add(res, res4);
    }
  }

  printf("%lld\n", res);
}

int main() {
  int t; scanf("%d", &t);
  while (t--) work();
  return 0;
}