Rail Fence Encryption

def Rail_Fence_Encryption():
    Plain_Text = input("Please enter some plain text\n-->")

    while len(Plain_Text) % 12 != 0:
        Plain_Text += "X"

    Cipher_Text = []
    Index_Pattern = [[0,6],[1,5,7,11],[2,4,8,10],[3,9]]
    Index_Pattern_Original_Length = [2,4,4,2]

    for Iteration in range(1,round(len(Plain_Text)/12)):
        for Index, List in enumerate(Index_Pattern):
            for Entry in range(Index_Pattern_Original_Length[Index]):
                List.append(List[Entry]+(12*Iteration))

    for Line in Index_Pattern:
        for Index_Value in Line:
            Cipher_Text.append(Plain_Text[Index_Value])

    print("".join(Cipher_Text))

    """
    The following text:
    hello hello hello there there thereX

    Mapped like this:
    h/////h/////h/////t/////t/////t/////
    /e/// /e/// /e/// /h/// /h/// /h///X
    //l/o///l/o///l/o///e/e///e/e///e/e
    ///l/////l/////l/////r/////r/////r

    Produces this:
    hhhttte e e h h hXlololoeeeeeelllrrr
    """

Rail_Fence_Encryption()