Temari are Japanese thread balls. You make a ball with scraps of fabric (I use old socks; a lot of people buy polystyrene balls three or four inches diameter), wrap it thickly with knitting yarn and then with sewing yarn so you have a compact and neat sphere with an embroiderable surface. Then you decorate it. The mathematical divisions needed to make the patterns, and the geometric patterns themselves, appeal to me. The finished articles are beautiful. They make lovely decorations. Google 'temari' for more info. I'll look up one of my favourite sites and post the link, anon.
