Comment by Tommah

I used this effect in my chess trainer (the link is in my profile). I have a file with 800 compressed chess positions, and I used a lot of tricks to get the file as small as I could. One trick was to invert the color of every piece on White's side of the board. In a typical position outside of the endgame, White's pieces will tend to be on his side of the board, and Black's will tend to be on his side. By inverting the piece colors on one side, I ended up with positions where almost all of the pieces are black, and here and there you'll have a white piece. It's similar to how most of the letters in text are lowercase, and occasionally you'll see an uppercase letter. I think I shrank the file by 5% or so this way.