Clue #4 is up, and probably there are lots of finished photos in the thread in the Ravelry group. I checked there for the first three clues, but for the last clue, I wanted to keep the mystery all the way. I had the chart in the pattern of course, but I'm not able to figure out what a lace will look like from seeing the chart. I love working from charts, I think it's much easier than written instructions (in fact, I would never have worked lace like this if it wasn't charted). But still, lace pattern making is a mystery to me, even without a mystery KAL. Even so, I can tell you a small secret - I have included a little lace (very simple), in my mystery mitten pattern. Introduction is up today.
Here's a closeup of clue #3 from TTL's mystery shawl: