'Grow this cell to *width* grid columns and *height* rows by expanding
horizontal spans and creating continuation cells to form vertical
spans.'

def _grow_to(self, width, height, top_tc=None):

    def vMerge_val(top_tc):
        if (top_tc is not self):
            return ST_Merge.CONTINUE
        if (height == 1):
            return None
        return ST_Merge.RESTART
    top_tc = (self if (top_tc is None) else top_tc)
    self._span_to_width(width, top_tc, vMerge_val(top_tc))
    if (height > 1):
        self._tc_below._grow_to(width, (height - 1), top_tc)
