source_code: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  
  public class C {
      public static void main(String[] args) throws Exception {
          BufferedReader buffer = new BufferedReader(new InputStreamReader(System.in));
          StringBuilder sb = new StringBuilder();
          int t = Integer.parseInt(buffer.readLine());
          while (t-- > 0) {
              int n = Integer.parseInt(buffer.readLine());
              ArrayList<Integer>list = new ArrayList<>();
              for (int i = 0; i < n; i++) {
                  int a = Integer.parseInt(buffer.readLine());
                  if (a == 1)
                      list.add(1);
                  else {
                      for (int j = list.size()-1; j >= 0; j--) {
                          if (list.get(j)+1 == a)
                              break;
                          list.remove(list.size()-1);
                      }
                      list.remove(list.size()-1);
                      list.add(a);
                  }
                  for (int j = 0; j < list.size(); j++) {
                      sb.append(list.get(j));
                      if (j == list.size()-1)
                          sb.append("\n");
                      else
                          sb.append(".");
                  }
              }
          }
          System.out.println(sb);
      }
  }
  