Learning matplotlib - axis not lining up

[SRG]

Hi. I'm learning matplotlib and have an issue. I have a scatter plot working perfectly. I'm trying to draw lines between two points but it seems to be on a completely different axis scale. Why isn't the line being drawn between the two points specified?

import matplotlib.pyplot as plt

points = []
points.append((1, 2, 10,2))
points.append((10, 2, 1,200))
points.append((1, 200, 799,799))
points.append((150, 702, 142,221))
points.append((799, 799, 400, 400))
points.append((142, 221, 799, 799))
points.append((11, 562, 142, 221))
points.append((145, 255, 11, 562))
points.append((170, 702, 145, 255))
points.append((14, 52, 170, 702))
points.append((314, 35, 14, 52))
points.append((414, 52, 314, 352))
points.append((14, 452, 414, 52))
points.append((14, 552, 14, 452))
points.append((514, 52, 14, 552))
points.append((14, 652, 514, 52))
points.append((614, 52, 14, 652))
points.append((714, 752, 614, 52))
points.append((750, 712, 714, 752))
points.append((703, 742, 750, 712))
points.append((714, 772, 703, 742))
points.append((400,400, 714, 772))

gridpointsX = [200,200,200,400,400,400,600,600,600]
gridpointsY = [200,400,600,200,400,600,200,400,600]

xp = []
yp = []
for point in points:
  xp.append(point[0])
  yp.append(point[1])
  # plt.plot([point[0], point[1]], [point[2], point[3]])


plt.plot([400,400], [714,772])
# plt.grid(True, markevery=200)

plt.plot(xp, yp, 'bo')
plt.plot(gridpointsX, gridpointsY, "+", ms=10, zorder=-1, lw=.2)

plt.axis([0,800,0,800])
plt.show()
# savefig('plotted.png')

[SRG]

Because it's supposed to be:

  plt.plot([point[0], point[2]], [point[1], point[3]])

[x1, x2],[y1, y2] not [x1, y1],[x2, y2]