#! /usr/bin/python3
# Recursively drawing a sine wave
from turtle import *
import time
import math


def draw_sine(x):
    if not x < 50:
        print("done")
    else:
        y = 30 * math.sin(.5 * x)
        setx(x)
        sety(y)
        penup()
        goto(x, y)
        dot()
        pendown()
        draw_sine(x + .25)

if __name__ == "__main__":
    x = -50
    penup()
    draw_sine(x)
    time.sleep(100)