"It's based on the principle of pi,"

I kept telling people, "You double the number of stitches every time you double the number of rows."
The older knitters would nod and move on to the next question. The younger knitters would stare at me and look for an explanation. This is what happens when you let people display a "pi-shawl". For the non-knitters among you I need to explain I suppose.
The "pi-shawl" was originally designed by Elizabeth Zimmerman - the "mother of modern knitting". EZ, as she is often known, "unvented" things. She did not slavishly follow patterns. She looked at knitting in new and different ways. Others have followed her since. I have prowled after her because I am simply too lazy to be bothered with the fuss of trying to follow the patterns of anyone else. 
One of the things she played with was a circular shawl which is constructed from the centre out. The start is usually nine stitches knitted into a circle followed by six rounds and then the stitches are doubled to eighteen, followed by twelve rounds and so on. There are many variations. Those interested may Google and find much more information.
But yesterday I kept having to explain this. The Embroiderer's Guild had borrowed one from me. It has Shetland lace patterns in it and I am teaching a class on the subject of Shetland lace for them in the summer. The embroiderers were right next door to the knitters and the shawl was displayed between the two. People were sent to ask me about it. And I discovered that a lot of younger people simply did not understand "pi". They had heard of it but they didn't understand the principle. "Something to do with how you work out how big the outside of the circle is..." was about as far as anyone got.
But, once explained, the comments were positive. Most of them thought that there was "too much knitting" involved. They want things they can finish quickly - if they knit at all. But there were some dedicated crafters among them who appreciated the idea if not the application.
There is a lot of basic mathematics in most crafts. The Senior Cat, who plays with  origami when it is too hot to be out in his beloved shed or garden, can tell you a lot about measuring once, twice and then three times to be sure before cutting a piece of timber. He knows about angles and curves too. He doesn't understand knitting but he could see the sense in the pi-shawl. 
Anyone who has ever done any patchwork or quilting understands how things "fit" into each other - or they should. It really isn't difficult. You need to know even  if you are just going to do what EZ called "blindly follow".
      "That's much too complicated," someone told me.
Someone else said, "I'd never be able to work that out."
Really?
I wonder what they teach in geometry these days?