vector preview problems

hey everyone!

I just started scripting python in gh and allready have a very basic problem.

i created a grid of points and an "attractor" point.

now i want to create vectors form each of the "gridpoints" to my attractor...
i could manage to get the lengths of these vectors in a list (to process them in a later state of the script) but somehow my vectors aren't displayed...maybe someone knows what the problem could be?
thanks in advance!

import rhinoscriptsyntax as rs
import Rhino as rc

gridpoints = [] #list with all the gridpoints
lengths = [] #list with vector lengths

#attractor
ptattractor = rs.AddSphere(attractor,radius)

#setting up the pointgrid
for i in range(0,Xwidth):
for j in range(0,Ywidth):
point = rc.Geometry.Point3d(i,j,0)
rs.AddSphere([i,j,0],radius)
gridpoints.append(point)

#setting up vectors from gridpoints to attractor
for pt in gridpoints:
vector = rs.VectorCreate(attractor,pt)
length = rs.VectorLength(vector)
lengths.append(length)

#test to see how many vectors are in list
print len(lengths)
for i in lengths:
print i

a=ghdoc.Objects.Geometries