import matplotlib.pyplot as plt import numpy as np  if __name__ == "__main__":     fig = plt.figure(figsize=(15.2, 8))     ax = fig.add_subplot(111)      R = 10     p0, q0 = [20, 0], [-20, 0]     k = 275      dist = lambda p1, p2: np.sqrt( (p1[0]-p2[0])**2 + (p1[1]-p2[1])**2 )     force = lambda r: - k / r**2      theta = np.linspace(-np.pi, np.pi, 50)     for t in theta:         p1 = [-R * np.cos(t), R * np.sin(t)]         if t < np.pi * 0.5 and t > -np.pi * 0.5:             r = dist(q0, p1)         else:             r = dist(p0, p1)         F = force(r)         ax.arrow(p1[0], p1[1], F * np.cos(t), F * np.sin(t), head_width=0.5, head_length=0.7, fc='k')      ax.annotate(r"+", xytext=(0,0), size=30, xy=(0,0), ha="center", va="center")     ax.annotate(r"Satellite", xy=(25,0), xytext=(15,0),                 size=30, va="center",                 arrowprops=dict(arrowstyle="fancy", fc='k'))     ax.set_xlim(-13, 25)     ax.set_ylim(-11, 11)     ax.plot(-R * np.cos(theta), R * np.sin(theta), linewidth=3.)     ax.axis('off')     plt.savefig('field tidal.svg', bbox_inches='tight', pad_inches=.15, transparent='true')