It's a dome with iris style opening that opens when you twist the dome.
It's all printed-in-place (as one piece), so no assembly required. The shells are separated by a very fine gap. There are hidden hinges, slots, and pins between the shells to create the mechanism. The door pieces actually still stick to the print bed and are cut free with a knife/pliers once the print is done.
I wrote a detailed tutorial on how to design this: my website http://eleccelerator.com/mech-iris/
Please check it out, there's a few dozen screenshots, alone with detailed explanation of what I did, and most importantly, why I did it that way. The goal is not to teach you what button to press, the goal is to teach you the logic behind creating a certain shape that has functions and requirements.
The CAD model is available in the tutorial but to save you a click, it's here hosted by Onshape
And because it's a Onshape model, you are free to fork the design and immediately make modifications. The model is created in a fully parametric fashion and with extensive use of relationships/constraints. To change the size, only the top variables need to be edited and the changes should propagate throughout the model without errors. This is how I am able to easily create three sizes without too much work. This is another important part of my tutorial.