sierpinski.py

# Write your code here :-)
# idea from this YouTube video: https://www.youtube.com/watch?v=kbKtFN71Lfs

import random
import turtle as t

def midpoint(point1, point2):
    # given two coordinates, find the point halfway between them
    x1, y1 = point1
    x2, y2 = point2
    x = (x1 + x2) / 2
    y = (y1 + y2) / 2
    return (x, y)
    
def plot_point(x, y, label=None, radius=2):
    # plots a single point in turtle
    t.penup()
    t.goto(x, y)
    t.pendown()
    t.circle(radius)
    if label:
        t.penup()
        t.goto(x+10, y)
        t.pendown()
        t.write(label, font=('Arial', 16, 'normal'))
    
#make three points of a triangle
triangle = {"a": (0, 200), "b": (-200, -100), "c": (200, -100)}

# make it go fast
t.speed(0)

# plot the initial triangle
for label, point in triangle.items():
    plot_point(*point, label=label)

# start at a point halfway between a and b
current_point = midpoint(triangle['a'], triangle['b'])
plot_point(*current_point)

# make a list of the vertices for later
vertices = list(triangle.values())

for i in range(1000):
    #pick one of the vertices at random
    destination = random.choice(vertices)
    # find a point halfway between the current point and the random vertex
    # make that the new current point
    current_point = midpoint(current_point, destination)
    plot_point(*current_point)
    
input("Type Enter to end")