# 2D List

def negate(L):
    result = L
    for row in range(len(result)):
        for col in range(len(result[row])):
            result[row][col] = result[row][col] * 2
    return result

print(negate([[1,2,3],[1,2,3],[1,2,3]]))

# Recursive function

def merge_characters (chars: 'list of strings and nested lists of strings') -> str:
    result = ""
    for element in chars:
        if type(element) == list:
            result = result + merge_characters(element)
        elif type(element) == str:
            result = result + element
    return result

def reverse_a_string(string):
    if string == "":
        return string
    else:
        return reverse_a_string(string[1:]) + string[0]


string = "ballsack"
print(reverse_a_string("string"))

def draw_lines(n: int, cavnas: tkinter.Canvas):
    width = canvas.winfo_width()
    height = canvas.winfo_height()
    num_lines = int((n+1) / 2)

    for i in range(num_lines):