#include <iostream>
 
using namespace std;
 
int main()
{
    int t,n,b,c,z=1,tab[1000];
 
    cin>>t;
 
    for(int i=0; i<t; i++)
    {
        cin>>n;
        {
            for(int j=0; j<n; j++)
            {
                cin>>b;
                tab[z]=b;
                z++;
            }
            z--;
            c=z;
            z=1;
            for(int j=0; j<c; j++)
            {
                if(z%2==1)
                {
                    z++;
                }
                else if(z%2==0)
                {
                    cout<<tab[z];
                    z++;
                }
            }
            z=1;
            for(int j=0; j<c; j++)
            {
                if(z%2==1)
                {
                    cout<<tab[z];
                    z++;
                }
                else if(z%2==0)
                {
                    z++;
                }
            }
            z=1;
            cout<<endl;
        }
    }
 
    return 0;
}
 

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