Some of you have seen pictures of the stripy garter stitch scarf I made as my first thing. This is what I'm working on now. It's an illusion scarf. You make the design with stripes of two different colours, one for the background and one for the image, and the bits you want to be able to see are made with purl stitches, so they're raised. From the front you only see stripes, but if you tilt the scarf, the picture emerges. Hopefully that explanation makes sense.
Now you see him...
...now you don't. Except you kind of still can, because of the lighting.