[Joey][1] has [this trick][2] of embedding the Windows logo image within the kbd tags. So 

    <kbd>![Windows Key][winlogo]</kbd> 

Looks like

<kbd>![Windows Key][winlogo]</kbd> 

----------

**Edit**: Here's a better one that shows the 4 parts clearly:

<kbd>![Windows Key][newwinlogo]</kbd> `<kbd>![Windows Key][newwinlogo]</kbd>`

 [newwinlogo]: https://i.sstatic.net/B8Zit.png

Although FWIW I like the old one much better:

<kbd>![Windows Key][oldwinlogo]</kbd> `<kbd>![Windows Key][oldwinlogo]</kbd>`

  [1]: http://superuser.com/users/2054/joey
  [2]: http://superuser.com/questions/501239/how-to-open-explorer-with-mouse-only/501248#comment599076_501248
  [winlogo]: https://i.sstatic.net/Rfuw7.png
  [newwinlogo]: https://i.sstatic.net/B8Zit.png
  [oldwinlogo]: https://i.sstatic.net/T0oPO.png