Sphere Lighting Proposal

Hey everyone , I am a beginner user for grasshoper. My problem was I can not create a void inside of my sphere. I would like to create 2 cm offset from each surface 1cm for glue and one cm is for outer . I really appreciate If anyone can help me.

3. Attach minimal versions of all the relevant files

Are you looking for something like this? Or is one of your two offsets vertical?

Sphere_Lighting_2019Dec29a.gh (13.2 KB)

This was just what I looked for , I really appreciate it. Step by step I will be more familiar with this new way of thinking. Thank you so much.