dice by tom | Python Fiddle

import random
# importing random to allow the random intger
import time
#importing time this is not needed but allows for the wait before restarting
def start():
    #This def allows the program to carry on running after each output
    print("Enter the number of faces you would like your die to have.")
    #Explaining what to input
    die = int(input("Choose from: 4, 6 or 12  "))
    #input for the interger that we will work with
    if die == 4:
        #if the die == 4 then run this code
        for x in range(1):
            #for x means change x into the range of 1, run this code once.
            print(random.randint(1,4))
            #select a random number between 1 and 4
            time.sleep(1)
            #sleep for a second
            return start()
        #return back to the start
    elif die == 6:
        for x in range(1):
            print(random.randint(1,6))
            #number between 1,6
            time.sleep(1)
            return start()
    elif die == 12:
        for x in range(1):
            print(random.randint(1,12))
            #between 1,12
            time.sleep(1)
            return start()
    else:
        #if the number is not 4 6 or 12 then run this
        print("You have inputed the wrong number, please enter 4, 6 or 12.")
        #saying you have to choose a number between 4, 6 and 12
        time.sleep(0.5)
        return start()

Browser Version Not Supported

Due to Python Fiddle's reliance on advanced JavaScript techniques, older browsers might have problems running it correctly. Please download the latest version of your favourite browser.
Chrome 10+ Firefox 4+ Safari 5+
IE 10+

Let me try anyway!

Python Fiddle

Python Cloud IDE