"in-shadow": inShadow(ci, cj),
"highlight-light": inHighlight(ci, cj) && lightSquare,
"highlight-dark": inHighlight(ci, cj) && !lightSquare,
"in-shadow": inShadow(ci, cj),
"highlight-light": inHighlight(ci, cj) && lightSquare,
"highlight-dark": inHighlight(ci, cj) && !lightSquare,