cheering up my office

I recently got a new assignment at work, and I now have a "for real" office, rather than an open/shared cubical. Since I spend so much time there, I decided to add a little something to cheer up the place. And since I won't be bothering other people with my choice, I figured that something could be a small cactus! I decided to go with a Mammillaria vetula, and display it in an interesting way:

My new office plant in its black desert.

 The cactus itself is planted in an interior pot (with soil) and then I filled the space between the interior pot and the glass container with decorative black sand. I'm pretty sure this plant won't grow very much (my office has no windows), but I think it's cute. And the other half of the plant got planted in the garden, so hopefully that one will grow!

I like the spikes that are growing out of the largest part of the cactus, they make it look "dangerous"...Hopefully it will survive in my office for a while, and no one will complain I'm keeping a dangerous plant. Now, do you think work will let me keep a small grow light in my office too? (ha! probably not...)