Tubes in grasshopper

Hi I am fairly new to grasshopper and I was wondering on how one would create tube like objects that lays over an irregular surface like a sphere. My idea I am trying to replicate is like how tree vines pan over a surface like this picture.

http://www.flickr.com/photos/fantasticthings/4490952210/

Any links, tutorials or downloads to definitions would be much appreciated or something similar to aid me. Sorry if this is a broad request but I am fairly new to the program so I need all the assistance I can get.

Thanks

Bill