const ii = (flipped ? this.size.x - 1 - i : i);
const jj = (flipped ? this.size.y - 1 - j : j);
let classes = this.getSquareColorClass(ii, jj);
const ii = (flipped ? this.size.x - 1 - i : i);
const jj = (flipped ? this.size.y - 1 - j : j);
let classes = this.getSquareColorClass(ii, jj);