I bought Knitting Nature last Friday and cast on for a swirling pentagon right away. Upon closer inspection at home, I found that this book is rife with typos. For example, on page 47, it says to use size 8 needles to achieve a 18x25 gauge in stockinette for the body, a size 6 needle for the 1x1 rib at the cuffs and hem, and a size 9 needle for the 1x1 rib in the swirling pentagons. Look at the volcano on Grumperina's initial attempt when she followed the instructions. I agree with her that the size 9 should have read size 6. Her finished sweater looks fantastic.
I made test swatches with some 98 cent yarn from Marukai Marketplace. The wrapper says 100% peruvian cotton made in Japan. I got 18 sts per 4" in stockinette with size 6 needles and a pentagon with 20 sts and size 5 needles measured 6 1/4" tall. It looked like I could make the 40" size (small) with this yarn if I cast on 22 sts per side for the pentagon. I went back to the store for more yarn.
They didn't have the same color, but I bought 14 balls of a lovely orchid pink color instead. I was about halfway through the pentagon when I realized that the pink yarn is considerably thinner than the taupe yarn. I tried doubling the yarn and the gauge came to 16 sts per 4". This sweater is not in my immediate future.
I was also interested in making the Mosaic Shrug on page 64. The instructions don't make any sense. If you want to make a pentagon, why would you cast on 80 stitches onto 4 needles and then work the decrease rows? The instructions for the decrease rows say to [k2tog, k to 2 sts before end of needle, ssk] 5 times!
Does anyone know if there is an errata for the book posted on the web yet? The designs are so lovely. I wish they had taken a little bit more time to copy edit the book.