I was looking through dishcloth patterns recently, because I had signed up for a swap and wanted to see lots of options. I came across the Optical Illusion cloth and just had to whip one up.
Some people do the blocks in stripes, but I think ye olde quilting way of doing it with light, medium and dark colours works just great, even in knitting.
My dark colour yarn, on closer inspection, was too thick and would have messed up my tension, so I improvised with the two colours I had (rather than going upstairs and rummaging around. I was on a roll).
So there you are, an optical illusion dishcloth! Kinda cute, non?
The written pattern is a bit funny, but it's garter stitch and slanted, so I'm sure most people can figure it out... I did every odd row plain knit, and every even row "decrease at one end and increase at the other." For numbers, just knit until you can pick up the number of stitches you need for the next block. It's sort of Log Cabin style, but the last block is seamed to the cast-on of the first block. Clear as mud, right?