<style>
.container { 
  writing-mode: vertical-lr;
  font-family: Monospace;
  font-size: 20px;
  height: 200px;
  width: 200px;
}

.inline_block {
  display: inline-block;
  width: 100px;
  height:100px;
  background-color: green;
}
</style>
<div class=container>some text<div class=inline_block></div></div>
