Am I stupid or we've never discussed the plumbing theme of the World Piece Tour stage?
Finally! World Piece Tour stage show has always been bit of an odditidy out there and discussred surprisingly little indeed.
That stage setup is so confusing. I get that they probably weren't quite ready yet to execute a show in the scale of what World Slavery/Somewhere on Tour/Seventh Tour would eventually reach, but given that there clearly is effort to go out with slightly more elaborate and extensive stage props, it's just a bit weird that they really chose to... go with plumbing, given the already rather impressive and striking visual offerings of their records.
I think MaidenRevelations covered it quite well.