Python Nim Implementation.

DrNim.py

print(
    "Welcome to Nim!:\n"+
    "A simple game, where you're allowed to take "+
    "one, two, or three marbles from a pile of 12.\n"+
    "You compete against the computer to take the "+
    "last marble.")

marbles = 12

def computerTake(amount):
    global marbles # Python goes full retard without this.
    print("I'll take "+   str(amount)  +" of the marbles.")
    marbles -= amount
    print("Now we have "+ str(marbles) +" marbles left.")

while marbles:
    print("\nMarbles: " + "o"*marbles)
    choice = int(input("1, 2, or 3?> "))
    marbles -= choice
    if choice in range(1, 4): computerTake(4 - choice)
    else: print("Stop cheating, sux0r!")

print("It looks like I win again!")