"Unable to find a high-resolution image of the hexahedron anywhere online for a project I was working on, about six months ago I modeled and rendered this myself, to the exact dimensions of the in-game model. I just realized I could upload it here and see what people thought :D I suggest viewing the full-sized render-- just hit "Download" above.

There are some more details about the process and toolset here: http://www.reddit.com/r/Fez/comments/1h31ab/h3x4h3dr0n/"