import matplotlib.pyplot as plt
import numpy as np
from math import *

def plarc(an,rad,de=4,sx=1,sy=1):
    x=[]
    y=[]
    an=radians(an)
    for i in np.arange(de):
        x.append(cos(i*an/de)*rad*sx)
        y.append(sin(i*an/de)*rad*sy)
    plt.plot(x,y,'o--r')

plarc(90,3,de=40,sx=1,sy=1)
plarc(180,3,de=40,sx=1,sy=1)
plarc(30,3,de=40,sx=1,sy=2)
plt.show()