Better late than never, I say! Ashforth and Plummer have been doing this for ages and I still remember the joys of knitting a Klein bottle after they got popular on the Knit List (does anyone here remember life before Ravelry?).
Pat Ashforth and Steve Plummer are two British math teachers who have been trying to answer questions like that for the last 20 years with their mathematical knitting projects. Together, the pair goes by Woolly Thoughts, and their site features a wide array of afghans, cushions, scarfs, and plush toys that visually express different mathematical ideas in brightly colored (and incredibly comfortable-looking) ways.
via The Verge (make sure to click through to the interview in The Guardian)