As I write this my beautiful Jeannie is in Paducah working on our retirement home. I mention this because Paducah happens to be the home of the National Quilt Museum (which just managed to stay above water level in recent weeks). And I mention that because a tweet from @MathBits just came across my desk with the image below.
Now if that looks like just any old pretty quilt, look again. The quilt is designed to represent the Quaternions (sometimes called the H group, and sometimes Q8) multiplication table ... In case you've forgotten (shame) the multiplication rules for Quaternions here they are :
As best I can tell, the quilt is the handy work of Professor Gwen L. Fisher of the Department of Mathematics at California State Polytechnic Univ., San Louis Obispo.
And if you need to see the whole multiplication relation explained, see the page here, with that and much more about Quaternions and quilts.