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: /*package whatever //do not write package name here */
  
  import java.io.*;
  import java.util.*;
  
  public final class GFG {
      static void check(String s){
         int len =  s.length();
        // System.out.println(len);
         Stack<Character> st = new Stack();
         if(len % 2 != 0){ System.out.println("No"); return;}
         else{
             for(int i = 0; i< len/2; i++){
                 st.push(s.charAt(i));
             }
             for(int i = len-1; i>=len/2; i--){
                 if(st.pop()!= s.charAt(i)) {System.out.println("No"); return;}
             }
            
             
             
         }
      System.out.println("Yes");
         
         
      }
  	public static void main (String[] args) {
  		//System.out.println("GfG!");
  		Scanner sc = new Scanner(System.in);
  		int t = sc.nextInt();
  		while(t-- > 0){
  		    String s = sc.next();
  		    check(s);
  		    
  		}
  	}
  }