description: A string is called square if it is some string written twice in a row. For example, the strings "aa", "abcabc", "abab" and "baabaa" are square. But the strings "aaa", "abaaab" and "abcdabc" are not square.
  
  For a given string s determine if it is square.
  
  Input
  
  The first line of input data contains an integer t (1 ≤ t ≤ 100) —the number of test cases.
  
  This is followed by t lines, each containing a description of one test case. The given strings consist only of lowercase Latin letters and have lengths between 1 and 100 inclusive.
  
  Output
  
  For each test case, output on a separate line:
  
    * YES if the string in the corresponding test case is square, 
    * NO otherwise. 
  
  
  
  You can output YES and NO in any case (for example, strings yEs, yes, Yes and YES will be recognized as a positive response).
  
  Example
  
  Input
  
  
  10
  a
  aa
  aaa
  aaaa
  abab
  abcabc
  abacaba
  xxyy
  xyyx
  xyxy
  
  
  Output
  
  
  NO
  YES
  NO
  YES
  YES
  YES
  NO
  NO
  NO
  YES
solution: import java.io.*;
  import java.util.*;
  
  // # 2 hrs
  
  public class new1{
  
  	public static void main(String[] args)  throws IOException{
      //	BufferedWriter output = new BufferedWriter(new OutputStreamWriter(System.out));
  		FastReader s = new FastReader();
  		int t = s.nextInt();
      	for(int z = 0; z < t; z++) {
      		//int n = s.nextInt();
      		String str = s.next();
      		int n = str.length();
      		if(n % 2 == 1) {
      			System.out.println("NO");
      			continue;
      		}
      		if(str.substring(0, n / 2).equals(str.substring(n / 2, n))) {
      			System.out.println("YES");
      		}
      		else {
      			System.out.println("NO");
      		}
      		
      		
      		
      		
      		
      		
      	}
      	//output.flush();
  
      }
  }
  
  
  class FastReader {
      BufferedReader br;
      StringTokenizer st;
      public FastReader() {
          br = new BufferedReader(new InputStreamReader(System.in));
      }
      String next() {
          while (st == null || !st.hasMoreElements()) {
              try {
                  st = new StringTokenizer(br.readLine());
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
   
      public int nextInt() {
          return Integer.parseInt(next());
      }
   
      long nextLong() {
          return Long.parseLong(next());
      }
   
      double nextDouble() {
          return Double.parseDouble(next());
      }
   
      String nextLine() {
          String str = "";
          try {
              str = br.readLine();
          } catch (IOException e) {
              e.printStackTrace();
          }
          return str;
  }}