This is, in my opinion, a masterpiece of pre-folding, you make one model, unfold it and bend it into another model. I pride myself of folding this from memory – not bad given I have not folded it in at least 15 years.

One piece of paper (photocopy A4 is not great as it frays after 3 or 4 creases on the same line) cut square, no additional cuts, no glue – all class.

Design by Jack Skillman, USA, 1965 (I first saw it in a Robert Harbin “Origami 2” book I own)