User blog comment:Mrob27/Block type 130/@comment-4501235-20111114184000/@comment-4501235-20111114184712

Oh, you wouldn't be able to view the bottom using glass or crystal. For some reason anything that moves can't be seen through semi-transparent blocks. You might be able to view it using the Transparency Bug, probably the method described in my comment on the Blue Crystal page would be best.