I have an ArrayList which contains Strings with a size of 1000. I am looping through that ArrayList and finding words and trying to form a square from them. For example as follows:

C A R D
A R E A
R E A R
D A R T

I have managed to get it working but it involves a lot of nested looping. If I am reading this right, this is O(n^4). Is there a more efficient way to do this.

void makeWord(ArrayList<String> arr){

    String first, second, third, fourth;
    for (int i = 0; i < arr.size(); i++) {

        first = arr.get(i);

        for (int j = 0; j < arr.size(); j++) {
            if(first.substring(1,2).equals(arr.get(j).substring(0,1)) &&
                    (!first.equals(arr.get(j)))){
                second = arr.get(j);
            }
            else {
                second = "    ";
            }

            if (!second.trim().isEmpty()) {
                for (int k = 0; k < arr.size(); k++) {
                    if (first.substring(2, 3).equals(arr.get(k).substring(0, 1)) &&
                            second.substring(2, 3).equals(arr.get(k).substring(1, 2)) &&
                            (!first.equals(arr.get(k)) && (!second.equals(arr.get(k))))) {
                        third = arr.get(k);
                    } else {
                        third = "    ";
                    }

                    if (!third.trim().isEmpty()) {

                        for (int m = 0; m < arr.size(); m++) {
                            if(first.substring(3,4).equals(arr.get(m).substring(0,1)) &&
                                    second.substring(3,4).equals(arr.get(m).substring(1,2))&&
                                    third.substring(3,4).equals(arr.get(m).substring(2,3)) &&
                                    (!first.equals(arr.get(m)) && (!second.equals(arr.get(m))))){
                                fourth = arr.get(m);
                            }
                            else {
                                fourth = "    ";
                            }

                            if (!(fourth.trim().isEmpty())) {
                                System.out.println(first);
                                System.out.println(second);
                                System.out.println(third);
                                System.out.println(fourth);
                                System.out.println(" ");
                            }
                        }
                    }
                }
            }
        }
    }
}