Draw lines connecting points between two separate one-D plots

As title, I am working on time-series alignment, and a visualization of the alignment result is desired.

To this end, I want to draw lines connecting "anchor points" generated by the alignment algorithm.

np.random.seed(5)
x = np.random.rand(10)      # time-series 1
y = np.random.rand(20)      # time-series 2
ap = np.array(([0, 4,  9],  # the anchor points
               [0, 9, 19]))

fig = plt.figure(figsize=(10,5))
ax1 = fig.add_subplot(211)
ax2 = fig.add_subplot(212)
ax1.plot(x, 'r')
ax2.plot(y, 'g')

the anchor points ap in the example specify the one-to-one "mapping" between the indices of two time series x and y, i.e., x[0] is corresponding to y[0]; x[4] to y[9]; and x[9] to y[19]. The goal is to draw lines between two separate plot to show the result of the alignment.

To connect two subplots in matplotlib you may use a ConnectionPatch.

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import ConnectionPatch

np.random.seed(5)
x = np.random.rand(21)      # time-series 1
y = np.random.rand(21)      # time-series 2
ap = np.array(([0, 5, 10],  # the anchor points
               [0,10, 20]))

fig = plt.figure(figsize=(10,5))
ax1 = fig.add_subplot(211)
ax2 = fig.add_subplot(212)
ax1.plot(x, 'r')
ax2.plot(y, 'g')

ls = ["-","--"]
c = ["gold", "blue"]

for i, row in enumerate(ap):
    for j, ind in enumerate(row):
        px = (ind, x[ind])
        py = (ind, y[ind])
        con = ConnectionPatch(py,px, coordsA="data", coordsB="data",
                      axesA=ax2, axesB=ax1, linestyle=ls[i], color=c[i])
        ax2.add_artist(con)

plt.show()