Yarn: Berroco Vintage Worsted - 50% Acrylic, 40% Wool, 10% Nylon
Needles: 4mm / US 6
Gauge: 5.5 stitches and 8 rows per inch - when its not being doubled over, that is.
Stitch Pattern: Pleating made with pulled up stitches in varying combinations.
Source: My new favourite knitting book, Montse Stanley's Knitters Handbook (the Reader's Digest version in this case), p. 151-152. As with most instructions in this book, the explanation of the technique is very basic, which is why I decided to experiment a little bit.
Comments: I'm trying to find the best way to make wrinkles. Not sure if I've found the best approach just yet. :)