#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << '\n';
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int inf = 0x3f3f3f3f;
long long infl = 0x3f3f3f3f3f3f3f3fLL;
long double infd = 1.0 / 0.0;
const long long MOD = 1e9 + 7;
const long double pi = 2 * acos(0.0);
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int tt = 1;
  cin >> tt;
  while (tt--) {
    string s;
    cin >> s;
    int x;
    cin >> x;
    int n = (int)s.size();
    string tmp = string(n, '1');
    for (int i = 0; i < n; i++) {
      if (s[i] == '0') {
        if (i - x >= 0) tmp[i - x] = '0';
        if (i + x < n) tmp[i + x] = '0';
      }
    }
    string s1 = string(n, '0');
    string w = tmp;
    for (int i = 0; i < n; i++) {
      if (i + x < n && w[i + x] == '1') s1[i] = '1';
      if (i - x >= 0 && w[i - x] == '1') s1[i] = '1';
    }
    if (s1 != s) {
      cout << -1 << '\n';
      continue;
    }
    cout << tmp << '\n';
  }
  return 0;
}
