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 javax.print.attribute.standard.MediaSize;
  import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.lang.reflect.Array;
  import java.util.*;
  import java.util.stream.Stream;
  
  public class Program {
  
      static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      static BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
  
      public static void main(String[] args) throws NumberFormatException, IOException {
  
          int cases = Integer.parseInt(reader.readLine());
          int mod = 998244353;
  
          while(cases-- > 0) {
  
  //            String[] firstLine = reader.readLine().split(" ");
  //            int n = Integer.parseInt(firstLine[0]);
  //            /*int k = Integer.parseInt(firstLine[1]);
  //            int x = Integer.parseInt(firstLine[2]);*/
  //
  //            int[] arr = convertToIntPrimitiveArray();
  
              String str = reader.readLine();
  
              if(str.length()%2 != 0) {
                  printNo();
                  continue;
              }
  
              int mid = str.length()/2;
  
              int i=0;
              int j=mid;
              boolean poss = true;
              while(j<str.length()) {
                  if(str.charAt(i)!=str.charAt(j)) {
                      poss=false;
                      break;
                  }
                  j++;
                  i++;
              }
  
              if(poss) {
                  printYes();
              }else {
                  printNo();
              }
  
  
  
  
          }
  
          out.flush();
  
      }
  
       public static int ub(long[] arr, long num) {
          int start = 0;
          int end = arr.length;
          int mid = 0;
  
          while(start<end) {
              mid = start + (end-start)/2;
              if(arr[mid] < num) {
                  start = mid+1;
              }else {
                  end = mid;
              }
          }
          return start;
       }
  
      public static int[] convertToIntPrimitiveArray() throws IOException {
          String[] str = reader.readLine().split(" ");
          return Stream.of(str).mapToInt(Integer::parseInt).toArray();
      }
  
      public static Integer[] convertToIntArray(String[] str) {
          Integer[] arr = new Integer[str.length];
          for(int i=0;i<str.length;i++) {
              arr[i] = Integer.parseInt(str[i]);
          }
          return arr;
      }
  
      public static Long[] convertToLongArray(String[] str) {
          Long[] arr = new Long[str.length];
          for(int i=0;i<str.length;i++) {
              arr[i] = Long.parseLong(str[i]);
          }
          return arr;
      }
  
      public static long[] convertToLongPrimitiveArray() throws IOException {
          String[] str = reader.readLine().split(" ");
          return Stream.of(str).mapToLong(Long::parseLong).toArray();
      }
  
      public static void printYes() throws IOException {
          out.append("YES" + "\n");
      }
  
      public static void printNo() throws IOException {
          out.append("NO" + "\n");
      }
  
      public static void printNumber(long num) throws IOException {
          out.append(num + "\n");
      }
  
      public static long hcf(long a, long b) {
          if(b==0) return a;
          return hcf(b, a%b);
      }
  
      public static int findSet(int[] parent, int[] rank, int v) {
          if(v==parent[v]) {
              return v;
          }
          parent[v] = findSet(parent, rank, parent[v]);
          return parent[v];
      }
  
      public static void unionSet(int[] parent, int[] rank, int a, int b) {
  
          a = findSet(parent, rank, a);
          b = findSet(parent, rank, b);
  
          if(a == b) {
              return;
          }
  
          if(rank[a] < rank[b]) {
              int temp = a;
              a = b;
              b = temp;
          }
  
          parent[b] = a;
          if(rank[a] == rank[b]) {
              rank[a]++;
          }
  
      }
  
      public static void makeSet(int[] parent, int[] rank, int v) {
          parent[v] = v;
          rank[v] = 0;
      }
  
      public static long modularDivision(long a, long b, int mod) {
          if(a==0) return 1;
          a %= mod;
          long res = 1L;
          while(b > 0) {
              if((b&1)==1) {
                  res = (res * a)%mod;
              }
              a = (a*a)%mod;
              b >>= 1;
          }
          return res;
      }
  
      public static void customSort(int[] arr) {
          int n = arr.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              int tmp = arr[i];
              int randomPos = i + rnd.nextInt(n-i);
              arr[i] = arr[randomPos];
              arr[randomPos] = tmp;
          }
          Arrays.sort(arr);
          return;
      }
  
      public static void customSortLong(long[] arr) {
          int n = arr.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              long tmp = arr[i];
              int randomPos = i + rnd.nextInt(n-i);
              arr[i] = arr[randomPos];
              arr[randomPos] = tmp;
          }
          Arrays.sort(arr);
          return;
      }
  
      public static long[] factorial(int n, int mod) {
          long[] fact = new long[n+1];
          fact[0] = 1;
          for(int i=1;i<fact.length;i++) {
              fact[i] = (i*fact[i-1] + mod)%mod;
          }
          return fact;
      }
  
      public static List<Integer> primeNumbers(int num) {
          boolean[] arr = new boolean[num+1];
          List<Integer> primes = new ArrayList<>();
  
          for(int i=2;i*i<=num;i++) {
              if(!arr[i]) {
                  for(int j=i;j*i<=num;j++) {
                      arr[j*i] = true;
                  }
              }
          }
  
          for(int i=2;i<=num;i++) {
              if(!arr[i]) {
                  primes.add(i);
              }
          }
          return primes;
      }
  
  
  }