yofx introduced us to Scratch in the post http://www.yofx.org/?p=97. Some months later I discovered a Scratch ap that draws curlicues. To help me understand the code, the author suggested I check out the book "Another Fine Math You've Got Me Into..." by Ian Stewart. Stewart writes the French edition of Scientific American's "Mathematical Games," a column started by Martin Gardner many years ago. Here are a couple of pages from his book.