Given a string like ABC, let's say its square is the result of writing it left-to-right along the top of a square and top-to-bottom along the left of the square, then filling in the rest of the square with backwards L shapes that connect the top instance of each character with its corresponding instance on the left. For example, ABC's square is:

ABC
BBC
CCC

Write a function called print_square that takes a (single-line) string and prints its square.