A variation of his convoluted structure.
Lines drawn in zigzag along a diagonal of a square on both sides (see its
diagram) cause the sheet of square paper to twist since these segments become alternating valley- and mountain- creases at folding. The diagonal is molded to a gentle S-curved 'mid-rib' and almost of the creases are formed into 'veins' in a leaf blade, simultaneously.
The object was displayed [put behind Trefoil Roses] in 5th annual convention held by Kansai branch of Japan Origami Academic Society(JOAS), on April 17-18, 2004 at Kobe, Japan.
Material: a sheet of square origami, without using adhesives.
Date: %Confirmation is in progress..%
Photo date: February 12, 2002
References:
Some continuation of "leaves and variations"
(Revised March 18, 2006)

7