The Space Sphere, Rick the Adventure Sphere, the Fact Sphere, and of course, Wheatley, all from Portal 2.
I've drawn Wheatley a bunch, but never actually drawn the other Cores before. And this was a good excuse to practice shading and blending.
There are so many amazing Wheatley designs out there, and I love them all. <3 I feel like mine is slowly solidifying.