So I did some science.
I then followed this science with heresy, because it's awesome, and here's what I ended up with: a dormant Chaos Gate, about half an inch thick. When activated, it produces a glowing tunnel that gives the appearance of being several feet long.
Why? For the glory of Chaos, of course!
Quick video showing how it's all put together:
https://youtu.be/JHh7IZqpGoY