writing-mode: horizontal-tb
    Blocks stack from top to bottom.
Box 1
    
      Box 2
    
      Box 3
    writing-mode: horizontal-tbBlocks stack from top to bottom.
writing-mode: vertical-rlBlocks stack from right to left. Text may be rotated 90 degrees.
writing-mode: vertical-lrBlocks stack from left to right. Text may be rotated 90 degrees.