Attractors exercise in Grasshopper Primer

Hello
for you it is clear what is GH primer, for me an surely others it is not clear. We will have to search with Google … So it is good to give link.
Also giving an image of a script is good but not enough. Why not giving the script ?
You can look here good advices

As it is a common question I recommand you to search a bit on internet and on old grasshopper forum

First and second image must be with line attractor, 3rd and 4th must be with point attractor.