I see clever hinged/cantilever shelves on TV ads. And say to myself (spot the engineer) "how do they counterbalance massed tinned food that could be 10 Kg different on any given day? & corner cupboards with 3/4 circular shelves that rotate out so you can see everything. And say to myself, "circle in square leaves unused shelf space that doesn't leave options on organisation".

Clever only looks clever. Organised shelf stacking is clever.

When I moved in to my abode the corner unit had hinges that opened 180^o and you had to open one to open the second. I put 270^o hinges in immediately. Mind you there is a lot of unused shelf space in order to see and extricate items. The nature of corner cupboards.