How to improve cone - make the bases more like a circle? - python-3.x

Question

I have a code for plotting a cone with some text and arrows like axes. How to change this code to get the bases of the cone looking like circles? Is the problem in the settings of margins? Or is it necessary to define circles in another way?
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits import mplot3d
from matplotlib.patches import FancyArrowPatch
from mpl_toolkits.mplot3d import proj3d
class Arrow3D(FancyArrowPatch):
def __init__(self, xs, ys, zs, *args, **kwargs):
FancyArrowPatch.__init__(self, (0, 0), (0, 0), *args, **kwargs)
self._verts3d = xs, ys, zs
def draw(self, renderer):
xs3d, ys3d, zs3d = self._verts3d
xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
self.set_positions((xs[0], ys[0]), (xs[1], ys[1]))
FancyArrowPatch.draw(self, renderer)
nn = 400 # number of points along circle's perimeter
theta = np.linspace(0, 2*np.pi, nn)
rho = np.ones(nn)
# (x,y) represents points on circle's perimeter
x = np.ravel(rho*np.cos(theta))
y = np.ravel(rho*np.sin(theta))
fig, ax = plt.subplots()
plt.rcParams["figure.figsize"] = [5, 5]
figsize = (5, 5)
ax = plt.axes(projection='3d') # set the axes for 3D plot
ax.azim = -88 # y rotation (default=270)
ax.elev = 13 # x rotation (default=0)
# Low, high values of z for plotting 2 circles at different elevation
loz, hiz = -15, 15
# Plot two circles
ax.plot(x, y, hiz)
ax.plot(x, y, loz)
# Set some indices to get proper (x,y) for line plotting
lo1,hi1 = 15, 15+nn//2
lo2,hi2 = lo1+nn//2-27, hi1-nn//2-27
# Plot 3d lines using coordinates of selected points
ax.plot([x[lo1], x[hi1]], [y[lo1], y[hi1]], [loz, hiz])
ax.plot([x[lo2], x[hi2]], [y[lo2], y[hi2]], [loz, hiz])
eps = 0.005
ax.plot([0, 0], [0, 0], [0, 20]) # extend in z direction
ax.plot([0-eps, 0], [0-eps, -5], [0-eps, 0]) # extend in y direction
ax.plot([0, 1.3], [0, 0], [0, 0]) # extend in x direction
ax.plot([0+eps, 0.6], [0+eps, -4], [0+eps, 16]) # v vector
ax.plot([0.63, 0.63], [-4, -4], [16, -0.005]) # vertical projection
ax.plot([0+eps, 0.6], [0+eps, -4], [0+eps, -0.005]) # to the beginning
ax.scatter(0, 0, 20, marker=(3, 0, 0), s=100, clip_on=False)
ax.scatter(0, -5, 0, marker=(3, 0, 43), s=100, clip_on=False)
ax.scatter(1.3, 0, 0, marker=(3, 0, 30), s=100, clip_on=False)
ax.scatter(0.6, -4, 16, marker=(3, 0, 80), s=100, clip_on=False)
ax.scatter(0.6, -4, -0.005, marker=(3, 0, 0), s=100, clip_on=False)
a2 = Arrow3D([0.14, -0.515], [-5.581, 1.358], [14.73, 4.983], mutation_scale=20, arrowstyle="-|>", color="k", connectionstyle="arc3,rad=0.3")
ax.add_artist(a2)
ax.text3D(0.23, -5.23, 23.33, r'$A$')
ax.text3D(1.41, 1.29, -2.7, r'$B$')
ax.text3D(-0.31, 1.46, -12.6, r'$C$')
ax.text3D(0.4, -5.48, 17, r'$D$')
ax.text3D(0.64, 1.57, -9.95, r'$E$')
ax.text3D(-0.2, -5.5, 15.73, r'$F$')
# Hide axes
ax._axis3don = False
# Save the figure (.pdf)
margins = { # vvv margin in inches
"left" : 1 / figsize[0],
"bottom" : -2.45 / figsize[1],
"right" : 1 - 0.5 / figsize[0],
"top" : 1 + 1.8 / figsize[1]
}
fig.subplots_adjust(**margins)
plt.savefig('output.pdf')
plt.show()
From this code I got the following output:
The desired output is bases looking like a circle.
This is the view from above:
It is not a circle but an ellipse.
Desired shape of the cone: