import numpy as np
from numpy import sum, zeros, less, where
import scipy as sp

import matplotlib.pyplot as plt
from matplotlib import collections
from matplotlib.colors import colorConverter

colors = [colorConverter.to_rgba(c) for c in
          ('r','g','b','c','y','m','k')]

fig = plt.figure()
ax = fig.add_subplot(1,1,1)
lines = collections.LineCollection([[[x,0], [x+1, 1], [x+2, 2]] for x in range(20)])
# lines.set_array(L_range)
lines.set_color(colors)
ax.add_collection(lines, autolim=True)
ax.set_xlim(0, 21)
ax.set_ylim(0, 2)
plt.show()