<html style="-webkit-writing-mode: vertical-rl"><body style="border:2px solid black; width:500px">
<div style="margin-right:1em; width:200px;border:2px solid maroon"><div style="float:right;width:100px;height:100px;background-color:lime"></div>
Here is some text in a vertical-rl block flow.  The block direction is right-to-left.<br>This line should also be vertical.</div></body></html>