I have taken a quick look at some of the other topics and throughout the site and I did not notice an answer to how you would denote a strikeout looking. I understand that an unfilled dot/circle seems to be a strike looking, and if it is the 3rd we can assume K looking, but how would you do write this aside from an actual backwards K. I'm thinking in terms of a computer program...so maybe KL (strikeout looking)?
Perhaps I missed something, I just stumbled onto your site and I would like to learn more about this, but I was hoping there was a quick answer.
Backwards K is the way to go. Not all symbols can be typed on the computer. In case you're curious, retrosheet play-by-play logs record a called third strike "K/C".
Another convention I have seen used quite a bit is this: K = strike out (called or unknown), Ks = strike out swinging.