Just a simple cube with minimal decoration. Size is 25x25x16 for the Encased Area, a bit bigger than that if we include the "decoration:
Uses Clear Leaded Glass form the Chipped mod and Vanilla Stone Brick Blocks.
I've used this on Prominence II and Steampunk, but other than "Chipped" Glass Blocks, which exist in most modpacks these days, you can use this on any version of Create that is set to the default 10000 blocks == Infinite Lava Source setting.