Drawing heart with math

MatHeart.py

# http://mathworld.wolfram.com/HeartCurve.html
from math import pi, sin, cos
import time
import numpy as np
r = 1
result = []
for i in range(38):
    result.append([])
    result[i] = list(map(lambda x: ' ', range(38)))

calc_x = lambda a: r * 16 * pow(sin(a), 3)
calc_y = lambda a: -r * (13 * cos(a) - 5 * cos(2 * a) - 2 * cos(3 * a) - cos(4 * a))
calc_d = lambda a: (calc_x(a), calc_y(a))
for a in np.arange(0.0, pi, .1):
    x, y = calc_d(a)
    result[int(16 + y)][int(20 + x)] = "O"
    x, y = calc_d(pi*2 - a)
    result[int(16 + y)][int(20 + x)] = "O"
    time.sleep(.05)
    print(chr(27) + "[2J")
    for i in result:
        print()
        for x in i:
            print(x, end='')
print("")