def paralline(nl=2, x0=0, y0=100, x1=33, y1=66):
p1, p2 = Point(x0, y0), Point(x1, y1)
s1 = Segment(p1, p2)
# Create a new Line perpendicular to s1 passing through the point p1
l1 = s1.perpendicular_line(p1)
l2 = s1.perpendicular_line(p2)
p1 in l1
p2 in l2
s1.is_perpendicular(l2)
s1.is_perpendicular(l1)
#p11 = subs_point(l1, s1.length)
# find coords of parallel nl segments from each side of the transect
x11, y11 = zeros(2*nl+1), zeros(2*nl+1)
x22, y22 = zeros(2*nl+1), zeros(2*nl+1)
j=0
for i in range(-nl,nl+1):
p11 = subs_point(l1, 1*i/s1.length) # divide unit segment on its length
x111, y111 = p11.args
x11[j], y11[j] = float64(x111), float64(y111)
p22 = subs_point(l2, 1*i/s1.length) # divide unit segment on its length
x222, y222 = p22.args
x22[j], y22[j] = float64(x222), float64(y222)
j+=1
# # Checking that segments are parallel and same length
# s2 = Segment(p11,p22)
# s2.is_parallel(s1)
# s1.length - s2.length
# plt.plot([x0, x1], [y0, y1])
# plt.plot([x11, x22],[y11, y22], 'k')
return x11, y11, x22, y22
