I would love to be able to create a square ring for my mall .. I would put assembling machines on the outside and inside of the ring using the ring of chests as a shared bus.
Sorry, only full rectangle chests. You could emulate a square ring by creating 4 different chests and then use some inserters/loaders to move items where they are needed. If those chests would be big I'd suggest limiting maximum chest inventory size to avoid performance issues.
