#include <bits/stdc++.h>
using namespace std;
long long f, a, b, x, c, q, d, w, a1, b1, c1, a2, g, b2, c2, n, m, i, j, k, l,
    o, p, t, y, r, q1, q2, mx, mx2, mn = 1000000000000, mn2 = 1000000000000;
string s, s1, s2, s3;
bool used[100005];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> t;
  for (y = 0; y < t; y++) {
    cin >> s >> x;
    q = 0;
    s2 = "";
    for (i = 0; i < s.size(); i++) {
      used[i] = 0;
      s2 = s2 + '0';
    }
    for (i = 0; i < s.size(); i++) {
      if (s[i] == '0') {
        if (i - x >= 0) {
          if (s2[i - x] == '1') q = 1;
          s2[i - x] = '0';
        }
        if (i + x < s.size()) {
          s2[i + x] = '0';
          used[i + x] = 1;
        }
      }
      if (s[i] == '1') {
        if (i - x >= 0) {
          if (used[i - x] == 1)
            ;
          else {
            s2[i - x] = '1';
            continue;
          }
        }
        if (i + x < s.size()) {
          s2[i + x] = '1';
          continue;
        }
        q = 1;
      }
    }
    if (q == 1)
      cout << -1;
    else
      cout << s2;
    cout << "\n";
  }
}
