#include <bits/stdc++.h>
using namespace std;
void solve() {
  string s, w, t;
  long long n, x, k = 0, cnt = 0, mx = -1000000007, mn = 1000000007;
  cin >> s >> x;
  n = s.length();
  for (int i = 0; i < n; i++) w.push_back('1');
  for (int i = 0; i < n; i++) {
    if (s[i] == '0') {
      if (i >= x) w[i - x] = '0';
      if (i + x < n) w[i + x] = '0';
    }
  }
  bool works = 1;
  for (int i = 0; i < n; i++) {
    if (s[i] == '1') {
      if (i >= x && w[i - x] == '1') continue;
      if (i + x < n && w[i + x] == '1') continue;
      works = 0;
    }
  }
  if (works)
    cout << w;
  else
    cout << -1;
  cout << "\n";
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n, tests = 1, prev = 0, i = 0;
  cin >> tests;
  while (tests--) {
    solve();
  }
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  std::mt19937_64 rng(
      std::chrono::steady_clock::now().time_since_epoch().count());
  return 0;
}
