Design a class to represent a rectangle with a user$-$specified non$-$negative width and length. You should include methods to determine the area and perimeter of the rectangle, and one which will determine whether or not your rectangle is a square. Also include a method to determine how many squares have ever existed in your program $($so for example, if I create a rectangle with a width and length of $2,$ then change the width to $3,$ then change the length to $3,$ you should indicate that two total squares have existed over the life of the program even though only one rectangle was created$).$

Write a main$()$ method that creates and changes several rectangle objects to show that your class works correctly