Block &BlockAt(const Block::Pos &pos) { return BlockAt(ToIndex(pos)); }
const Block &BlockAt(const Block::Pos &pos) const { return BlockAt(ToIndex(pos)); }
Block &BlockAt(const Block::Pos &pos) { return BlockAt(ToIndex(pos)); }
const Block &BlockAt(const Block::Pos &pos) const { return BlockAt(ToIndex(pos)); }