Draw Phyllotaxis with turtle graphics

phyllotaxis.py

import math
from turtle import *

shape('circle')
speed(0)

c = 15

for n in range(500):
    a = n * 137.507764050
    r = c * math.sqrt(n)
    
    x = r * math.cos(a)
    y = r * math.sin(a)
    
    up()
    goto(x, y)
    down()
    dot(20)