#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    int x;
    string s;
    cin >> s >> x;
    int n = s.length();
    char w[n + 2];
    for (int i = 0; i < n + 2; i++) {
      w[i] = '@';
    }
    bool canchange[n + 2];
    for (int i = 0; i < n + 2; i++) {
      canchange[i] = true;
    }
    int i;
    for (i = 0; i < n; i++) {
      if (i - x < 0 && i + x >= n) {
        if (s[i] == '1') {
          break;
        }
        continue;
      } else if (i - x < 0) {
        if (!canchange[i + x] && (w[i + x] != '@' && w[i + x] != s[i])) {
          break;
        }
        w[i + x] = s[i];
        canchange[i + x] = false;
      } else if (i + x >= n) {
        if (!canchange[i - x] && (w[i - x] != '@' && w[i - x] != s[i])) {
          break;
        }
        w[i - x] = s[i];
        canchange[i - x] = false;
      } else {
        if (s[i] == '1') {
          if (w[i - x] == '@') {
            w[i - x] = '1';
            canchange[i - x] = false;
          } else if (w[i - x] == '0') {
            if (!canchange[i - x]) {
              if (!canchange[i + x] && w[i + x] == '0') {
                break;
              }
              w[i + x] = '1';
              canchange[i + x] = false;
            } else {
              w[i - x] = '1';
              canchange[i - x] = false;
              w[i + x] = '0';
            }
          } else {
            w[i + x] = '0';
          }
        } else {
          if (w[i - x] != '0') {
            if (!canchange[i - x]) {
              break;
            } else {
              w[i - x] = '0';
              canchange[i - x] = false;
            }
          }
          if (w[i + x] != '0') {
            if (!canchange[i + x]) {
              break;
            } else {
              w[i + x] = '0';
              canchange[i + x] = false;
            }
          }
        }
      }
    }
    if (i < n) {
      cout << -1 << endl;
      continue;
    }
    for (i = 0; i < n; i++) {
      if (w[i] != '@') {
        cout << w[i];
      } else {
        cout << '1';
      }
    }
    cout << endl;
  }
}
