ploting dot

[scidam]

Look at countourf function from the matplotlib package.

In general, pseudocode for your task would be the following:

from matplotlib import pyplot as plt
import numpy as np

list_of_lists = np.array(list_of_lists) # probably you will need to convert your data to numpy 2d array

X, Y = np.meshgrid([tau1, ... , tauN], [x1, ... , xM]) # pseudocode!
# probably you would use X, Y = np.meshgrid(np.linspace(tau1, tauN, 100), np.linspace(x1, xM, 100)) instead
plt.countourf(X, Y, list_of_lists)
plt.show()

Note: this is pseudocode only, you need to adopt it for your needs.