from matplotlib.matlab import *

delta = 0.025
x = y = arange(-3.0, 3.0, delta)
X, Y = meshgrid(x, y)
Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)

# difference of Gaussians
im = imshow(Z2-Z1, interpolation='bilinear')
axis('off')
show()