source_code: //I'm Whiplash99
  import java.io.*;
  import java.util.*;
  public class C
  {
      public static void main(String[] args) throws Exception
      {
          BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  
          int i,N;
  
          int T=Integer.parseInt(br.readLine().trim());
          StringBuilder sb=new StringBuilder();
  
          while (T-->0)
          {
              N=Integer.parseInt(br.readLine().trim());
  
              int[] a=new int[N];
              for(i=0;i<N;i++) a[i]=Integer.parseInt(br.readLine().trim());
  
              int end=1;
              int[][] ans=new int[N][N+10];
  
              ans[0][0]=1;
              for(i=1;i<N;i++)
              {
                  while (true)
                  {
                      if(ans[i-1][end]==a[i]-1) break;
                      end--;
                  }
                  for(int j=0;j<end;j++) ans[i][j]=ans[i-1][j];
  
                  ans[i][end]=a[i];
                  end++;
              }
  
              for(i=0;i<N;i++)
              {
                  for(int j=0;j<N&&ans[i][j]!=0;j++)
                  {
                      sb.append(ans[i][j]);
                      if(ans[i][j+1]!=0) sb.append('.');
                  }
                  sb.append("\n");
              }
          }
          System.out.println(sb);
      }
  }