#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

#define            ll              long long
#define            pb              push_back
#define            mp              make_pair
#define            loop(i,a,n)     for(int i=a;i<=n;++i)
#define            clr(x)          memset(x,0,sizeof x)
#define            min3(a,b,c)     min(a,min(b,c))
#define            max3(a,b,c)     max(a,max(b,c))
#define            min4(a,b,c,d)   min(a,min(b,min(c,d)))
#define            max4(a,b,c,d)   max(a,max(b,max(c,d)))
#define            fast            ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define            pii             pair<int,int>
#define            pll             pair<ll,ll>
#define            pli             pair<ll,int>
#define            pil             pair<int,ll>
#define            FF              first
#define            SS              second
#define            PI              acos(-1.0)
#define            bug             cout<<"ok"<<endl;

using namespace std;
using namespace __gnu_pbds;

typedef tree<int , null_type,less<int>,
       rb_tree_tag, tree_order_statistics_node_update> anik;

const int MOD = 1e9 + 7;
const ll MX= 1e9;
const ll INF = 1e9;

main()
{
    int t;
    cin>>t;
    while(t--)
    {

        string s,ans;
        cin>>s;

        int n,l;
        cin>>n;

        l=s.length();

        bool f=0;
        for(int i=0;i<l;++i)
        {
            if(s[i]=='1' && i<n && i+n<l)
            {
                ans[i+n]='1';
            }
            else if(s[i]=='0' && i<n && i+n<l)
            {
                ans[i+n]='0';
            }
            else if(i>=n && i-n<n)
            {
                if(s[i]=='1')
                    {
                        ans[i-n]='1';
                        if(i+n<l)ans[i+n]='1';
                    }
                    else
                    {
                        ans[i-n]='0';
                        if(i+n<l)ans[i+n]='0';
                    }
            }
            else
            {
               if(s[i]=='1')
               {
                   if(i+n<l)ans[i+n]='1';
                   if(ans[i-n]=='1')continue;
                    else f=1;break;
               }
               else
               {
                   if(i+n<l)ans[i+n]='0';
                   if(ans[i-n]=='0')continue;
                   else f=1;break;
               }
            }
        }


        if(f==1)cout<<-1<<endl;
        else
        {
            for(int i=0;i<l;++i)cout<<ans[i];
       cout<<endl;
        }

    }


}