This charming 6-piece modular cube is designed by Francesco Mancini and is included in his booklet “Mancinerie”, which I think I purchased from the BOS shop online:
Each face is a twisted square. Folded from A5 sheets, the pre-creasing is pretty easy and the twist is satisfying.
I chose 3 colours and the realised that the suggested locking mechanism would see untidy coloured flap overlaps, so invented a new method of locking the modules together so the edges were colour separate.
I like this module, and may explore its applications further. Francesco offers a number of decorative variations to this basic shape and some of them look lovely.