source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.IOException;
  import java.util.Deque;
  import java.util.ArrayList;
  import java.io.UncheckedIOException;
  import java.util.List;
  import java.io.Closeable;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.util.ArrayDeque;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   */
  public class Main {
      public static void main(String[] args) throws Exception {
          Thread thread = new Thread(null, new TaskAdapter(), "", 1 << 29);
          thread.start();
          thread.join();
      }
  
      static class TaskAdapter implements Runnable {
          @Override
          public void run() {
              InputStream inputStream = System.in;
              OutputStream outputStream = System.out;
              FastInput in = new FastInput(inputStream);
              FastOutput out = new FastOutput(outputStream);
              CCompressionAndExpansion solver = new CCompressionAndExpansion();
              int testCount = Integer.parseInt(in.next());
              for (int i = 1; i <= testCount; i++)
                  solver.solve(i, in, out);
              out.close();
          }
      }
  
      static class CCompressionAndExpansion {
          Node end = new Node(null, -1);
          FastOutput out;
  
          public void solve(int testNumber, FastInput in, FastOutput out) {
              int n = in.ri();
  
              List<Node> seq = new ArrayList<>(n);
              Deque<Node> dq = new ArrayDeque<>(n);
              end = new Node(null, -1);
              dq.addLast(end);
              for (int i = 0; i < n; i++) {
                  int x = in.ri();
                  while (true) {
                      Node last = dq.peekLast();
                      if (last.nextChild != x) {
                          dq.removeLast();
                          continue;
                      }
                      last.nextChild++;
                      dq.addLast(new Node(dq.peekLast(), x));
                      break;
                  }
                  seq.add(dq.peekLast());
              }
  
              this.out = out;
              for (Node node : seq) {
                  print(node);
                  out.println();
              }
          }
  
          void print(Node root) {
              if (root.p != end) {
                  print(root.p);
                  out.append('.');
              }
              out.append(root.index);
          }
  
      }
  
      static class FastInput {
          private final InputStream is;
          private StringBuilder defaultStringBuf = new StringBuilder(1 << 13);
          private byte[] buf = new byte[1 << 13];
          private int bufLen;
          private int bufOffset;
          private int next;
  
          public FastInput(InputStream is) {
              this.is = is;
          }
  
          private int read() {
              while (bufLen == bufOffset) {
                  bufOffset = 0;
                  try {
                      bufLen = is.read(buf);
                  } catch (IOException e) {
                      bufLen = -1;
                  }
                  if (bufLen == -1) {
                      return -1;
                  }
              }
              return buf[bufOffset++];
          }
  
          public void skipBlank() {
              while (next >= 0 && next <= 32) {
                  next = read();
              }
          }
  
          public String next() {
              return readString();
          }
  
          public int ri() {
              return readInt();
          }
  
          public int readInt() {
              boolean rev = false;
  
              skipBlank();
              if (next == '+' || next == '-') {
                  rev = next == '-';
                  next = read();
              }
  
              int val = 0;
              while (next >= '0' && next <= '9') {
                  val = val * 10 - next + '0';
                  next = read();
              }
  
              return rev ? val : -val;
          }
  
          public String readString(StringBuilder builder) {
              skipBlank();
  
              while (next > 32) {
                  builder.append((char) next);
                  next = read();
              }
  
              return builder.toString();
          }
  
          public String readString() {
              defaultStringBuf.setLength(0);
              return readString(defaultStringBuf);
          }
  
      }
  
      static class Node {
          Node p;
          int index;
          int nextChild = 1;
  
          public Node(Node p, int index) {
              this.p = p;
              this.index = index;
          }
  
      }
  
      static class FastOutput implements AutoCloseable, Closeable, Appendable {
          private static final int THRESHOLD = 32 << 10;
          private final Writer os;
          private StringBuilder cache = new StringBuilder(THRESHOLD * 2);
  
          public FastOutput append(CharSequence csq) {
              cache.append(csq);
              return this;
          }
  
          public FastOutput append(CharSequence csq, int start, int end) {
              cache.append(csq, start, end);
              return this;
          }
  
          private void afterWrite() {
              if (cache.length() < THRESHOLD) {
                  return;
              }
              flush();
          }
  
          public FastOutput(Writer os) {
              this.os = os;
          }
  
          public FastOutput(OutputStream os) {
              this(new OutputStreamWriter(os));
          }
  
          public FastOutput append(char c) {
              cache.append(c);
              afterWrite();
              return this;
          }
  
          public FastOutput append(int c) {
              cache.append(c);
              afterWrite();
              return this;
          }
  
          public FastOutput println() {
              return append('\n');
          }
  
          public FastOutput flush() {
              try {
  //            boolean success = false;
  //            if (stringBuilderValueField != null) {
  //                try {
  //                    char[] value = (char[]) stringBuilderValueField.get(cache);
  //                    os.write(value, 0, cache.length());
  //                    success = true;
  //                } catch (Exception e) {
  //                }
  //            }
  //            if (!success) {
                  os.append(cache);
  //            }
                  os.flush();
                  cache.setLength(0);
              } catch (IOException e) {
                  throw new UncheckedIOException(e);
              }
              return this;
          }
  
          public void close() {
              flush();
              try {
                  os.close();
              } catch (IOException e) {
                  throw new UncheckedIOException(e);
              }
          }
  
          public String toString() {
              return cache.toString();
          }
  
      }
  }
  
  