#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1000000007;
void __print(long long int x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  long long int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
void solve() {
  string s;
  cin >> s;
  long long int x;
  cin >> x;
  long long int n = s.length();
  string ans(n, '1');
  for (long long int i = 0; i < n; i++) {
    if (s[i] == '0') {
      if (i - x >= 0) {
        ans[i - x] = '0';
      }
      if (i + x < n) {
        ans[i + x] = '0';
      }
    }
  };
  bool check = true;
  for (long long int i = 0; i < n; i++) {
    if (s[i] == '1') {
      bool l = false;
      bool r = false;
      if (i - x >= 0 && ans[i - x] == '1') {
        l = true;
      }
      if (i + x < n && ans[i + x] == '1') {
        r = true;
      }
      if (l == false && r == false) {
        check = false;
        break;
      }
    }
  }
  if (!check) {
    cout << -1 << endl;
  } else {
    cout << ans << endl;
  }
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int t;
  cin >> t;
  while (t--) {
    solve();
  }
}
