Function grid_row 

pub fn grid_row<C>(children: C) -> GridRow<C>
where
    C: PieceSeq,

One row of a grid: each child is a cell, assigned to columns left to right. Outside a grid a row degrades gracefully to a plain row. Rows are transparent carriers — the grid places their cells directly — so decorating a grid_row itself is unsupported (decorate the cells, or the grid).