Update revision 4:
I added an extra wall so it keeps more stable, it can still be moved with ease but it don't put strain to the thin wall pieces. I think I am satisfied an close my work on it.

Cup holder for your desktop, well it comes out of sitting on a desk and not having a good spot for my coffee mug. I have then taken it through some revisions and after 3 major revisions I ended up in 3.5 where it actually works for almost all the cups I want on my desk.