import matplotlib.pyplot as plt
from mpl_toolkits.axisartist.axislines import SubplotZero
import numpy as np
plt.rc('font', family='serif')
plt.rc('svg', fonttype='none')
plt.rc('text', usetex=0)

delta = .01
x = np.arange(-1, 1, delta)
y = np.arange(-1, 1, delta)
X, Y = np.meshgrid(x, y)
Z = ((X ** 2) * Y) - (Y ** 3) - (X ** 4)

fig = plt.figure(figsize=(8,8))
ax = SubplotZero(fig, 1, 1, 1)
fig.add_subplot(ax)

ax.contour(X, Y, Z, [0], linewidths=2, colors='black')
ax.grid(True)

for border in ['left', 'right', 'top', 'bottom']:
    ax.axis[border].set_visible(False)

ax.axis['xzero'].set_visible(True)
ax.axis['yzero'].set_visible(True)
ax.set_xticks([-1, -.5, .5, 1])
ax.set_yticks([-1, -.5, .5, 1])
ax.minorticks_on()
ax.set_xlim([-1.1, 1.1])
ax.set_ylim([-1.1, .6])
ax.set_aspect(1)